House Rules to Make Autocannons Not Suck

[Demiurge]

So I don't derail the Great Wyrm MOTW article with a rant about how unconscionably bad autocannons are in battletech, I thought I would put forward some homebrew rules to make these things viable.  Maybe not amazing, and certainly no match for the cheesy glory that is clan energy weaponry, but at least good enough that I am comfortable with them.

The reason I'm currently uncomfortable with autocannons is because they break my suspension of disbelief.  Under the current rules, autocannons are basically so bad that either their representation vs. other weapons is drastically uncharitable, or all the clans, great houses and minor powers have had a centuries-long lapse of sanity in continuing to field these things.

Here are my beefs with autocannons:


-Autocannons have poor damage per tonne of ammunition compared to missiles.  Once you account for missile scattering, autocannons pull slightly ahead of LRMs, but they are still squarely behind SRMs.  Streak SRMs, of course, clobber autocannons in terms of efficiency (and everything else that isn't an energy weapon)

This doesn't make any sense, either from a real-world engineering perspective or from a game balance perspective.  Compare the M456 105mm HEAT round from the mighty L7 tank cannon to an RPG-29, which is also 105mm.  The 105mm gun round is much faster, but also much smaller than the RPG-29.  On the other hand, high-velocity 105mm tank guns are way too heavy for infantry to carry around, but missile launchers are not.  So rocket propelled munitions are a trade-off; the ammunition is much bigger and heavier, but the launchers themselves are much lighter.  The reasons for this are fundamental to internal ballistics, and so unlikely to change in the future.  Battletech gets this halfway right, of course; the guns are heavier than the rocket launchers... but the ammo is effectively heavier too (less damage/tonne).  Why would anyone use these awful things?

-Autocannons have poor damage output relative to tonnage.

This doesn't make sense from an in-universe perspective.  Most battles in the BT universe are fought at the end of lightyears-long logistical trains, and attacking forces are constrained by what they can cram into their dropships.  Surely generals and engineers would try to economize on tonnage, and try to use only weapons that give the most zap for the least weight?  Surely, after centuries of warfare spread over nearly all the worlds that man has ever colonized, someone would have realized that autocannons completely suck and they should be using almost anything else instead?

-Autocannons are significantly less flexible than missiles.

This is a pure game balance perspective.  A rocket motor offers much more gradual acceleration than the barrel of a gun, so it makes sense that more sophisticated and delicate electronics could be stuffed into the nose of a missile than into the shell of an autocannon.  But if a weapon is basically bad, but still commonly fielded by almost everyone, I would reasonably expect it to do something cool on the side to balance out its lack of obvious merit.

-Autocannons do not meet the criteria of suckage

There are plenty of other weapon systems in Battletech that suck.  Bombast lasers, for example, are terrible.  But they are fluffed as the hobby-horse of a specific manufacturer that started marketing the things when their engineers threw up their hands because they couldn't turn the system into anything workable.  Bombast lasers are rare, basically a fluff curiosity that's just common enough to be worth having rules for.  Rocket launchers also suck, and are fairly common, but they are fluffed as cheap weapons that are fielded in numbers only by the most budget-conscious forces that can afford little better.  The Hunchback IIC is a bad mech, but it is designed such that it will occasionally perform outrageous acts of over-the-top heroism and carnage.  Given the culture that uses this design, it's pretty clear why it would stick around the TO&Es of the clans.

Autocannons are ubiquitous, their diverse and numerous users all having somehow failed to notice how bad they are.

So, in short, all autocannons underperform.  In general, 10s and 20s are usable while 2s and 5s are garbage.  LBXs are the exception, with 2s and 5s having a niche as AAA and long-range crit seekers.  LBXs have carved out a unique niche as vehicle killing weapons, AAA (although the big ones are a bit short ranged for that) and crit seekers.  Standard autocannons and ultras need more help, with small caliber standards and ultras needing the most help of all.

So with all that in mind, here are my optional autocannon rules.  They're intended to be used all at once, but obviously you can pick and  choose if you think that wiser.  They're also intended to keep existing designs legal and require minimal changes to the rules sheets.  Finally, they're intended to be as simple as possible so as not to slow down gameplay.  Obviously, the use of these rules will distort the battle value of any unit that has an autocannon.

Two-mode Fuse for Standard Rounds

Autocannon "standard" ammunition is actually a marvel of miniaturized fusing technology.  Variable-delay fusing existed in the mid 20th century, but the manufacturing technology that could transform crude, hand-adjusted fuses into induction-timed, proximity fused, mass produced munitions that were ubiquitous down to the lowly class-2 autocannons took a little more time.  Essentially, autocannons are a hybrid HEAT/light armor piercing warhead with an electronically programmed fuse that can attack targets in two different ways.

Autocannon shells contain a forward-facing proximity sensor that can trigger their shaped-charge anti-armor warheads a few fractions of a second before impact.  This gives optimal standoff and implosion geometry to get the most performance possible out of the warhead.  Autocannon shells also have a light armor piercing cap internally and an all-aspect delayed impact fuse.  If required, the proximity sensor can be switched off and the shells programmed to explode a few fractions of a second after they smash into something.  This mode is devastating to static structures like buildings and the internal structure of mechs, although it does a poor job of penetrating military-grade armor.

The standard mode is with the proximity fuse on, and in this mode all "standard" autocannon munitions (for ACs, LBX, RACs, UACs, etc) behave as normal.  In delayed-fuse mode, the autocannon will do double damage to all buildings and all internal structure except for reinforced-type internal structure.  In delayed-fuse mode the autocannon will do half damage to armor of all types except for armor with a BAR of less than 10, exclusive.  The player attacking with the autocannon must decide which shell fusing mode they are using when they make the attack (the electronic fuse is set in the autocannon, the shells aren't smart enough to determine what they're about to hit).

Specialty ammunition types do not have a delayed-fuse mode.

Increased Damage Against Battle Armor

Class-2 autocannons of all types do 4 damage against battle armor when firing standard ammunition, based on whatever rationale bearhunter ACs do bonus damage to BA.  Battle armor resists big hits well, but not lots of little hits that above some threshold.  Or something.  Class-5 autocannons of all types do 7 damage against battle armor while protomech autocannon-4s do 6 against BA.

This increased damage does not apply when firing any sort of specialty ammunition.

Increased Ammunition Per Tonne

All standard autocannons have 140 damage per tonne of ammunition, so that's 70 rounds for -2s, 70 rounds for -5s, et cetera.  Hyper-velocity autocannons are 80 damage per tonne of ammunition, so 40 for -2s, 4 for -20s, et cetera.  Caseless autocannons have 200 damage per tonne of ammo.  Protomech autocannons go up to a whopping 160 damage per tonne because (mutters something about superior clan technology, composite case designs, piezometric ceilings and efficiency) it would just be too hard to increase those by anything that isn't an integer since they pay per kilogram.

This situates autocannons between LRMs and SRMs for ammunition efficiency, enough that they wouldn't obviously be failing to pull their weight in centuries of campaigns' op-evals.

Optionally you can bump up gauss rifle ammo per tonne if you think gauss rifles should be inherently more ammo efficient than autocannons.  Also, optionally, you can have all ammunition bins perform as though they have CASE, all CASE bins perform as though they have CASE II, and have all CASE II bins, and CASE II also prevents pilot damage from ammo explosions.  The current ammo explosion rules penalize ammo weapons pretty heavily, and don't make very much sense.  Isolated ammunition storage was pretty much a solved problem in the 1970s with the M1 Abrams.  Why would things get so much worse in the 31st Century?

Autocannon Failures

Ultra autocannon jams, standard autocannons using rapid-fire mode rules, and ammunition-related mishaps in caseless and hyper velocity autocannons can be un-jammed per rotary autocannon rules.  Does it make any sense to you that a military would field weapons that have a 1/36 chance of bricking themselves as bread and butter for centuries?  It didn't make any sense to me either.  Caseless and hyper velocity are likewise so dangerously unreliable that they would obviously never leave the test stands, much less see limited production.  Also, I thought it made more sense to consolidate jamming/failure rules on the various flavors of autocannon rather than have several different, and more punitive ones.  The game gets slightly more streamlined, and an underperforming weapon category gets some love, win/win.

Ultra Autocannon Hyperburst

In the late 20th Century, Soviet small arms engineers began work on a radical type of infantry rifle that combined an internally recoiling barrel with an extremely fast cycling burst mechanism in order to fire bursts that did not have their dispersion affected by the rifle's recoil.  This work culminated in the AN-94 Abakan rifle, which saw limited issue into the early 21st Century.

Ultra Autocannons are that, but way bigger.  The Soviet AN-94 had a mixed reputation for mass-produce-ability and reliability, so it obviously took some time before engineers were confident enough to attempt to scale up their design.  Many a prototype ultra autocannon tore itself to pieces on the test range before the design was ready for mass production.

When firing in two-shot mode and at a single target (i.e. not using the multiple targets rules from TO), the to-hit roll is also a margin-of-success roll.  If the to-hit roll is greater than the target number by 2 for UAC-2s, 3 for UAC-5s, 4 for UAC-10 and 5 for UAC-20s, then skip the cluster hits roll, both shots strike the same location.  Roll for location normally.  If the to-hit roll is greater than the target number, but not by the margins listed above, the number of shots that hit and the locations where they hit are resolved normally.

Counter-Defilade Mode for LBX

If a unit is obscured by cover that is the same height as the unit being obscured (e.g. a battlemech is hiding behind cover 2 levels tall), and the unit obscured is immediately adjacent to the cover it is obscured from its attacker by, LBX cluster munitions may be used to attack it per LRM indirect fire rules if there is a spotter.  If the unit is obscured from its attacker by cover that is taller than the unit being obscured, or if it is hiding around a corner, then it cannot be attacked with LBX cluster munitions.  The proximity sensor fuse time gate is "smart" but it isn't brilliant.  Attempting to use the fuse settings to get the munition to detonate just behind a target when attacking it from the front is similarly out of the question.

LBX cluster munitions are essentially miniaturized, sensor-fused cluster bombs shot out of a cannon.  Again, they are nothing that an early 21st century commander would be unfamiliar with, but great strides in manufacturing technology allowed these advanced munitions to be mass-manufactured and distributed out of the barrels of cannons like so much candy out of a pinata.  Each cluster carrier has a proximity sensor that can be time-gated to ignore cover for a certain distance, and then go active once past a certain distance.

New Ammo Types

The standard autocannon's feed system is admirably omnivorous, being able to load, fire, and extract a number of non-standard ammunition types that the original designers could never have foreseen.  LBX autocannons use a high-low pressure system that prevents damage to the sophisticated electronics in the submunitions of their cluster shells, and as a result their ammunition is completely incompatible with standard autocannons, and vice versa.  Ultra autocannons use counter-rotating revolving cylinders that also reciprocate and fire binary ammunition that is wildly incompatible with anything exotic.  Ultra autocannons are fidgety enough with the ammunition carefully tailored for them, sticking anything strange in their feed systems is totally out of the question!  There was initial optimism at NAIS that rotary autocannons would prove compatible with a wide array of specialty munitions, but qualification trials have long since dashed that hope.  The specialty munitions simply were not made robust enough to survive the high speed of the feed systems in RACs.  Hyper-velocity autocannons and caseless autocannons have proven too rare to be worth furnishing with compatible, specialty ammunition although such ammunition could easily be developed if there were any demand for it.

But bog-standard autocannons proved able to accommodate several new ammunition types, even after the initial introduction of novel types in the late 31st century.

GLATGM ammo:  Taking a page from Soviet tank designs of the late 20th century, designers realized that firing a missile (specifically, a Gun Launched Anti-Tank Guided Missile) out of a gun might be useful.  Furthermore, the missile could be broken up into two parts that would be snap-assembled in the loading tray of the autocannon before being chambered in the gun (this is exactly how Russian gun-launched missiles work).  The designers also realized that only the AC-20 had a wide enough bore to accommodate a worthwhile missile.

GLATGM ammo is for standard AC-20s only.  GLATGM ammo is exactly the same as a thunderbolt-10 in terms of range and shots per ton, but it develops the same 7 heat as a standard AC-20 shot.  For campaign purposes, it should not be considered interchangeable with thunderbolt-10 ammunition; the missiles have been designed from the ground up to work in autocannon feed systems.

HESH ammo  HESH (High Explosive Squash Head) consists of a relatively thin-walled, insensitive explosive that deforms and flattens against the target.  Once it has spread out an achieved maximum contact area with the target, it detonates, creating a shock wave inside the target that can cause spall to rip off of the inside of the target's armor plate.  This effect can cause "scabbing" off of the inside of a target even if the HESH round doesn't penetrate.  HESH is also particularly devastating against walls.

HESH ammunition was largely abandoned in the early 21st century due to the proliferation of early composite armors.  However, the development of ultra-brissant, high-density explosives in later centuries made the concept viable once again.

HESH ammunition is for all standard and light autocannons.  HESH ammunition does 2 points less damage than normal, down to a minimum of 1.  HESH ammunition does double damage to buildings (so, 2, 6, 16, 36).  HESH ammunition has a +1 to-hit modifier.  HESH does half damage (round down) to battle armor and infantry.  If a HESH round hits an armored target, but does not remove all of the armor on hitting it, and the amount of armor remaining on the target is equal to or less than the amount of damage the HESH round inflicted, roll on the determining critical hits table with a -1 modifier.  If there are more points of armor remaining than the HESH round inflicted damage, there is no effect.  If the HESH round removes all the armor and damages the internal structure, critical hits are resolved normally.

...



Thoughts?

[Sabelkatten]

I still think simple is best:

+1 damage to all ACs
No minimum range
AC/2s put out 0 heat
-2 flak bonus to all ACs

This is intended for introtech games, but works mostly OK for the rest. Precision ammo do get a bit OP, thought, and UACs still need unjamming rules like RACs.

[Kharim]

Have You ever considered alternative ammuntion types? There are quite a few and they make AC's into real swiss knives. Put flak into AC2 become VTOL's nightmare. Load AC20 with precision rounds and become the god of death. Stationary target? Hope You have some AC20 AP rounds in your ammo bins.
Infantry harrasment? Make them flechettes rain and dont slip on the remaining goo.
Also AC's are both BV and CBill cheap.

[lucho]

No changes to the rules are necessary; autocannons perform just fine when used correctly. For example, Kharim is spot on about alternative ammunition. Then there heat inducing weapons: autocannons chuckle at Plasma Rifles and infernos, while flashbulbs find themselves with a genuine dilemma.

Now, if you really want to make autocannons more attractive and discourage flashbulbs without major complications here is my proposal (extensively tested. It worked well in practice, although it never eliminated Flashman and Penetrator type flashbulbs  :-\ ): http://bg.battletech.com/forums/index.php?topic=25737.msg582197#msg582197

[Sabelkatten]

Problem is, the correct way to use ACs is "almost never". Yeah, precision ammo - if done right it can get a conventional AC up to the level of common energy weapons, barely. LB2 and LB10 for AA and anti-vehicle. If flak wasn't "advanced" for some insane reason the AC/2 would be useful in 3025.

As for heat effects? Come on, AC make that worse. Not only do you have to carry exploding ammo, you now have less heat sinks to handle the excess heat!

I can vouch for my alternative for the simple reason that when designing a mech it makes common ACs a viable choice. Previously PPC or AC/10 was a no-brainer: PPC for range and ammo independence, AC/10 for fluff? Now the alternative is "more damage" instead.

[Frabby]

As a GM, you can handwave virtually any effect into special ammunitions. Autocannons are as versatile as your scenario makes them.

Oh, and for the record, I think the AC/2 is underrated. I like it.

[RunandFindOut]

In general my answer where possible is just to adjust the weight and crits and boost ammo count per ton in some of them.  Take any autocannon reduce weight and crits by a third, rounding down if necessary.  That alone makes things more even along with making the alternative ammo 'standard' instead of advanced and the same count per ton as normal ammo.

[Kharim]

Any time You mess with weight, damage, range, heat or ammo per ton, You mess up Battle Value's balance. One change can have a lot of unforseen consequences. For example- if you cut AC tonnage by third, how does Gauss Rifle look now? To heavy for the damage it does and to expensive in BV compared to AC10. Furthermore Light PPC becomes useless when compared with AC5, every LBX becomes useless because they now pay extra tonnage for ability to fire clusters. And what about Clan UAC's? Problems just keep stacking.                     

Autocannons are cheap, and they perform as a cheap weapon should. You get what you pay for- big, clumsy, explosive gun. Easy to maintain and feed. Hard to use in field of battle. Their usability changes over the eras, same with every other weapon. If you think AC's fare weak compared to missiles and energy, then I say why ever use IS Large Laser when I can do almost the same with Clan ER Medium?

You feel they are to weak? Use optional rapid fire autocannon rule from TacOps. Try alternative ammo. Use the AC equipped units properly, taking their battlefield role into consideration.

The only change I would ever consider is UAC unjamming. Which is actually an often used house rule as it offers the same usability as RACs have.

[Tai Dai Cultist]

Want to make autocannons look better? Take away double heat sinks. 

As Kharim explained, the advance of technology hasn't been kind to basic, rapidfire exploding shell-throwers.  Autocannons really only ever had one advantage over energy weapons and that was heat efficiency.  DHSs took that away, and it's gone forever barring the absence of those DHSs.

Also to Kharim's point: removing DHSs would have massive effects, far beyond making autocannons more attractive again.  You'd probably be better off just doing no lostech whatsoever (e.g. a Succession Wars game)

[RunandFindOut]

Any time You mess with weight, damage, range, heat or ammo per ton, You mess up Battle Value's balance.

Well then I guess it's good I don't USE BV as a balance tool. The Gauss rifle remains useful simply by dint of being a low-heat long range heatcapper.  LightPPC hasn't even been invented yet in the eras I tend to play.  LBX doesn't matter because if it's a campaign where we're comfortable with altering the autocannons in such a manner I delete the LBX series entirely and just make cluster ammo an alternate ammo type.  Also what makes you think ultra autocannons suddenly have a huge weight disadvantage.  When I say autocannons get dropped in weight and crits I mean ALL autocannons.

Problems just keep stacking.

You assume those things are problems, mostly I find they either don't actually matter or are not actually problems from my point of view.                     

You feel they are to weak? Use optional rapid fire autocannon rule from TacOps. Try alternative ammo. Use the AC equipped units properly, taking their battlefield role into consideration.  The only change I would ever consider is UAC unjamming. Which is actually an often used house rule as it offers the same usability as RACs have.

Good for you meanwhile I'll continue doing what I and my friends have been doing for many years regardless of your opinion.  I already use alternate ammo and actually make it available in the succession wars and raise it's ammo per ton count back up to the same as ordinary ammo.  I've weighted in with the fix I judged to be most useful for the problem, don't like it that's no skin off my nose.

[Cryhavok101]

Personally, were I going to improve ACs, I would do it in two steps the first stage improvement would be to develop the ammo. I would develop all the special ammo types for LBX, Ultra and Rotary ACs. Then advance the ammo itself by coming up with new ammo types. Not sure I would use ones in the OP, but I would want to be at least equaling the utility of the missile launcher ammo types.

The second step would be to improve the weapons themselves. Two major things I would concentrate on here: Make everything that can jam be able to be unjammed much like RACs can be. Make ACs that easily explode (HVACs) be built with CASE-like construction that causes any such explosion to be vented safely away from the 'Mech/vehicle rather than into your ammo bins.

As far as other house rules go I would probably add a rule that makes it so when you are hit by a ballistic weapon you have an extra penalty to any resulting piloting skill rolls to avoid falling. This representing the kinetic impacts of the rounds shoving the 'Mech around.

Personally I have no intention of actually using house rules to that effect, but that is the direction I would take it. As it is, I am okay with weapons becoming obsolete, or at least subpar, because that is what the weight of history does to weapons. As we develop newer more effective weapons, older ones fall by the wayside, like swords and bows.

[Snimm]

It's true that from a game mechanics perspective, it's hard to justify using autocannons.

However, as has been stated previously, they are cheap technology that don't require much expertise to repair and maintain, relative to, say, energy weapons or missile electronics.

The problem, of course, is that you don't see these issues if you aren't playing in a long-term roleplaying scenario where availability of supplies may be unreliable.  Remember that in the original 3025 world in which Battletech originated (and, I suppose, the Dark Age era), everything was supposed to be a slapped-together, use-what-you-have-at-hand mentality of warfare.  Obviously, that went away with the advent of the Clans and changed the balance of a lot of things.

I mostly play Battletech in the Against the Bot (AtB) campaign, and I am grateful to have at least a few autocannons to start out due to availability issues of the other categories of weapons during certain contracts.  But I think your typically casual gamer doesn't want to delve in that deeply.

[Hptm. Streiger]

OK, the following will only consider the Intro Tech aspect. The reason is simple that I always though that the tonnage balance is possible in Intro. 60ton Mech = 60ton Mech

However the specific values for a AC make them only valuable as secondary armament - the AC5 on the MAD-3R full fills a role that can hardly be made better with a energy weapon - (that you could drop PPC and AC5 for 3 Large Laser + 8 heatsinks might be a different story - Flashman style)

So there are two options: 1st you drop the 10 free heat sink rule - only allow rating/25 heatsinks (8 for the CN9-A) the CN9-AL is still the better but the advantage is not that big anymore.

Second - you tweak the values - for example the average change from AC5 to PPC - would you do it with a AC5 that deal 8dmg and has 12 shots?
To add 2 points for the AC10 might be enough this will make it a tin can opener.
You can also modify the "ranges" to help the ACs- increase the short range for the price of a reduced medium range would also be a major buff for most guns.

Just to show it in a  chart:


as long as you take a weapon only everything is neat.
Consider Free Heatsinks and the energy weapons become much better - DHS becomes not that important in this scenario - but i consider to make some comparisons for example 4 large laser vs 2 ppc + ac5 just for fun.

Before you asked.... the Benchmark is based on a program based dice roller - that rolls how many shot (not hits) are necessary to bring a maximum armored mech of each tonnage down. the hit modifer is based on 4 + 1(walking) + target movement (generic per weight +1->+4) and range.
In the next step how many shots per range band are necessary - 0 when target is out of range
done several times to reduce the margin of error.
Destruction: both legs; CT; 3xengine crits; 2xgyrohits; pilot death

as you can see - Gauss is king - heavy damage, long range, almost no heat,

[Nebfer]

As for me
For the purpose of calculating damage for a knock down role, ACs (well all ballistics really) have a +2 dmg, As such 5 AC-2s will equal 4 medium lasers for making that 20 dmg PSR (or a AC-10 and a large laser) rather than 10 AC-2s as is the case now.

In determining if they cause a Critical hit they gain a +1 to that role

AC-2s produce no heat, AC-10s 2, and AC-20s 5
LBXs all have a -1 heat (so yes LBX-5s = zero heat)
Lights also -1 (so yeas no heat from both systems)
Ultras UAC-2 zero heat in single shot, 1 in double shot
UAC-5 no change, UAC 10 & 20 are per regular ACs (3 and 5)
RAC-2 no heat in single shot, assumed to produced .5 heat per shot in rapid mode (6 shots produce 3 heat)
RAC-5 1 heat per shot, with a -1 heat (to a min of 1, 1 shot 1 heat, 2 shots 1 heat, 3 shots 2 heat, 6 shots 5 heat)

Specialty ammo is now factored as having 80% of the ammo per ton as regular ammo (AC-10 specialty ammo will have 8 shots vs 10 with regular, and not 5 like it is now) rounded down.

For jamming Ultras can now be unjamed like a RAC (though I view this as an upgrade, hey we fixed the issue, so IS UACs in the 3030-3065 era still perma jam).

Not a improvement per say but I do like the idea of Ultras and RACs making individual hit roles per shot (with a +1 modifier on that second shot, or every even round (I.e. RAC firing 2, 4 or 6 shots will generate +1, +2 & +3))

[Red Pins]

I use the metalstorm method, single barrel with pre-packed, electronically-fired rounds.  Capable of using all ammo types, in preset order.  Capable of burst fire, up to the full number of rounds up the spout but with increasing difficulty aiming.  I don't have the files on the box anymore, but I think the AC/20 tube had 5 rounds for seven tons.  Tub and twenty rounds of AC/2 for 3-4 tons, I think.

Made fast plinkers with AC/2s quite obnoxious, not so bad for /20s, but too heavy for normal use when you could just buy the reloading gun and more than one ton of ammo.

[Snimm]

Interesting.  So it's almost like a one shot weapon in the AC  class,  but it's one ton instead of one round of shot, and with a set order if you mix ammo types?

[Red Pins]

Kind of.  Originally, I Just made my best guess of the mass of just the barrel and a ton of ammo.  From there, I reasoned if LB-Autocannons could fire solid and pellet, there was no reason to restrict ammo type.  But you have to load and fire them in order.  For example, I designed a standard AC/20 tube; slug/slug/shot/slug/shot.  Fire a 3-round burst, and you roll two slug locations and THEN the number of pellets that hit, then the individual locations, just like a standard LB-20X.  The rules stay the same.

It was meant to allow light units like my AU's Extra-Light Mechs to use AC/2s or put a single tube of AC/20 on a Light backstabber.  You can see the action here, on you tube;
https://www.youtube.com/watch?v=wKlnMwuCZso

This was the last update for the i-ACs of my AU's 'Unique Technology' rules before my playtester moved to Edmonton;

Improved Autocannon (I-AC)
   Despite the heat efficiency of Autocannons, advances in heatsinks and energy weapons have diminished their presence on the battlefield.   Looking for weapons systems adaptable to modern warfare, the Civil Government has successfully combined the 21st century Metalstorm system with the modern Autocannon, providing compact, heat efficient weapons capable of flexibility unmatched by current designs.
   I-ACs take advantage of several centuries of development in ballistic weapons to provide cutting edge weight-to-damage ratios; the Metalstorm concept, used in large caliber grenade launchers before being abandoned by 2050, takes advantage of these developments to provide a rate of fire similar to Rotary Autocannons.

Game Rules
   I-ACs are useless after firing their pre-loaded ammo until the barrel is exchanged, but offer an increased rate of fire at a growing cost in accuracy.  I-AC/2 and /5s fire Bursts of six rounds per Turn, I-AC/10s fire Bursts of four, and I-AC/20s Bursts of two.

              Heat     Dam              Range     Ammo    Wt        Space          Tech
Weapon          Std(Aero)      Std (Aero)       M/S/M/L (Aero)    (barrel)  (tons)   M  E  CV  SV  F  SC  DS Rating
I-AC/2                 0*(0*)              2(2)            4/6/12/18 (Long)      45          3       1   2    1     1    1   1     1      F
I-AC/5                 0*(0*)              5(5)         3/5/10/15 (Medium)    20          4       1   3    1     2    1   1     1      F
I-AC/10                1(1)              10(10)        0/4/8/12 (Medium)     10          6       1   4    1     4    1   1     1      F
I-AC/20                3(3)              20(20)           0/3/6/9 (Short)          5          7       2    -    1     8    1   1     1      F
* - See Notes

Notes:
•   I-ACs are able to use special- and mixed ammo, in any order and any type except Caseless.  Players must record the type of ammo in order of firing.
•   I-ACs may fire single rounds or in Bursts.  Players must specify the number of rounds to be fired before the weapon is fired.
•   Heat is cumulative with each shell fired.  I-AC/2s and /5s do not generate heat for single shots; for each multiple of 2 rounds fired, one heat is generated.
•   Damage is allocated by shell, in order of rounds fired, following the rules for specialty ammo.
•   I-ACs roll on the Cluster Hits table to determine the number of rounds that hit the target.
•   I-ACs may fire a single round or Bursts.  When firing a single Burst, I-ACs do not receive a to-hit penalty and roll on the Cluster Hits table normally.
•   I-ACs may fire up to four Bursts in a single Turn, but players must make a to-hit roll for each Burst with a cumulative to-hit penalty.  Each Burst after the first requires its own to-hit roll (with a cumulative +2 to-hit penalty) and Cluster Hit table roll.
Ex.  An I-AC/2 needs a 3 to hit.  Because the to-hit number is low, the owner decides to risk the maximum number of Bursts in an attempt to kill his target.  The first Burst, without a to-hit penalty, requires a 3 (3+0), which the Player makes easily.  Rolling on the Cluster Hits table, he sees five have hit the target.  Checking the list of ammunition, he sees that all are standard rounds, and rolls hit locations for all five before proceeding.
The second Burst suffers from the first cumulative penalty, requiring a 5 (3+0+2). Rolling on the Cluster Hits table, he finds that five more standard rounds have hit the target, and rolls hit locations for all five before proceeding.
The third Burst requires a 7 (3+0+2+2), which he makes narrowly.  Checking against the Cluster Hits table he finds 3 rounds hit the target and rolls locations for all three.
The fourth Burst brings him to his first specialty ammunition, a six-round Burst of Precision ammo.  (Note the added mass of the specialty ammo has no effect on the I-AC/2.)  The ammunition provides a –2 to-hit modifier, giving him a to-hit number of 7 (3+0+2+2+2-2) for the second time.  If the fourth Burst had been standard ammo, it would have been a 9 (3+0+2+2+2).
•   If a Burst contains mixed ammunition types each round must be individually rolled in the order of firing and a hit location determined before going on to the next Burst.

Note the mistakes made in their rules; a 'Burst' is always five rounds, and you don't 'roll on the Cluster Hits table normally', you roll per round, in order.  (It was a real pain in playtest with mixed ammo, which is why the 'standard' AC/20 tube was invented.  When we used a tube of mixed AC/2 we wrote on the back of the record sheet to keep specialty ammo a surprise.)

[Sockmonkey]

AC rounds always seemed too darn heavy to me. Each one weighs as much as an SRM.
But I digress. Fact is, there are only two things that are going to make people use ACs.
Either actually make cost and/or availability a factor in all your games when creating mechs, or improve the ACs in some way thus changing their BV.
You have to pick one.
People are not gonna give up their DHS.

[Fear Factory]

To make AC's and Missiles better in introductory play, I'm liking the idea of using a Margin of Success that gives extra damage.

AC's - MoS of 2 or 3, + 1 damage.  4 or more, +2 damage.  All AC's get a -1 bonus for AA attacks.

Missiles - MoS of 2 or more, +1 on the missile hit chart.

The core rules don't change, no need to mess with stats, makes ammo weapons more appealing, and it's easy enough to understand that it won't bog down gameplay.

[Daryk]

AC rounds always seemed too darn heavy to me. Each one weighs as much as an SRM.
But I digress. Fact is, there are only two things that are going to make people use ACs.
Either actually make cost and/or availability a factor in all your games when creating mechs, or improve the ACs in some way thus changing their BV.
You have to pick one.
People are not gonna give up their DHS.

On cost and availability, the need to keep buying ammunition still gives the logistical edge to energy weapons.

[Sockmonkey]

On cost and availability, the need to keep buying ammunition still gives the logistical edge to energy weapons.

Assuming DHS are widely available yes. If they're fluffed as less available then the parts to maintain them get rarer and more expensive too. Whereas AC ammo is everywhere. I'm not real big on that solution though.
The RACs would easily be competitive if they let you get off two or three shots before a  jamming roll.
Plus there should be RAC 10s and 20s.

[Daryk]

Even with SHS, I think energy weapons still have the edge, at least for 'mechs and fusion vehicles.  It's the 10 free HS in the engine that tip the balance.

[Sockmonkey]

Even with SHS, I think energy weapons still have the edge, at least for 'mechs and fusion vehicles.  It's the 10 free HS in the engine that tip the balance.

True, even with intro level tech an ML boat Hunchback conversion has more firepower and can blast away all day.

[Hafergulden]

The houserule we settled on was of the Burst Fire type. We kept it as simple and straightforward as possible – AC/2s may fire 5 shots,  and AC/5s may fire 3 shots, using ammunition and generating heat as normal for each single shot (i.e., rapidfiring an AC/2 eats up 5 shots and builds up 5 heat). Roll on the appropriate cluster table to determine number of shots that actually hit the target, roll separate hit location for each shot that does hit.

That’s it. It has worked very well for us so far. The only problem is the AC/10, which, if you allow it to fire 2 shots, is slightly overpowered; if you leave it at 1 shot, it remains slightly underpowered. (AC/20 is perfectly fine as is.)

If you stick to pre-made designs, their limited ammo load and heat capacity serves very nicely to keep everything balanced and makes AC-armed ’Mechs a viable and fun choice, but not overpowering. It’s one of only two or three house-rule we use.

[Fear Factory]

Also, I always felt the AC/2 and 5 should have been bumped up 1 point each.  Maybe even make the 5 do 7 damage.  If the ammo is recalculated to reflect this:

AC/3 ammo (32)
AC/7 ammo (14) OR AC/6 ammo (16)

I really think that having the AC/2 do small laser damage with a long reach brings it up to par with other weapons in the game, instead of making it an overweight machine gun or long range SRM clusters.

Bumping up the AC/5 to 7 actually makes it compete better with the Large Laser and PPC.  Bumping it up to 6 almost achieves the same thing.  So much so that it could be a valid replacement because of the trade off in heat, something most can't even justify at 5 damage and 8 tons.  The AC/10 is still arguably much better, giving you that PPC punch with almost no heat.

I just like the idea of having light ballistics doing damage that is different than LRM/SRM clusters.  It creates more variety without breaking the game.  But yeah, rather than make a few simple changes for the sake of modernizing the game and encouraging use, just argue about it for 20 years and wonder why no one plays anymore OR boats lasers.

EDIT:  Oh, I'm also talking about ALL autocannons for this (Ultra, LB-X, Light, Rotary)  The increase in damage (all around) would make them different than LRM/SRM launchers and make them competitive with double heat sinks in play.

[Empyrus]

The houserule we settled on was of the Burst Fire type. We kept it as simple and straightforward as possible – AC/2s may fire 5 shots,  and AC/5s may fire 3 shots, using ammunition and generating heat as normal for each single shot (i.e., rapidfiring an AC/2 eats up 5 shots and builds up 5 heat). Roll on the appropriate cluster table to determine number of shots that actually hit the target, roll separate hit location for each shot that does hit.

That’s it. It has worked very well for us so far. The only problem is the AC/10, which, if you allow it to fire 2 shots, is slightly overpowered; if you leave it at 1 shot, it remains slightly underpowered. (AC/20 is perfectly fine as is.)

If you stick to pre-made designs, their limited ammo load and heat capacity serves very nicely to keep everything balanced and makes AC-armed ’Mechs a viable and fun choice, but not overpowering. It’s one of only two or three house-rule we use.

Interesting solution but this does indeed cause problems with bigger ACs. And more importantly, this makes rotary and ultra autocannons worthless unless those are also buffed similarly (eg Ultra/5 fires up to 3 double shots, total of 6 shots though heat starts becoming an issue along with ammo use). Perhaps it is fine for intro-tech level games, but for anything else with other types of ACs...


I had an idea of modifying autocannons as a weapons to be burst-fire weapons that fire 3 shots each every time. This required me to limit their values to 3/6/9 and remove one class of ACs (as AC/12 that fires 3 shots would have 3 chances of head-shotting a 'Mech and would be way too good).
But this was part of an BTU arsenal re-work, since the result overlap cause ultras and rotaries become useless, and the system being also overlapping with LB-X type would lead them being somewhat pointless as well. With so many changes to merely ACs, i figured i might as well rework everything else to reduce amount of weapons.

[Xeno426]

Personally I have no intention of actually using house rules to that effect, but that is the direction I would take it. As it is, I am okay with weapons becoming obsolete, or at least subpar, because that is what the weight of history does to weapons. As we develop newer more effective weapons, older ones fall by the wayside, like swords and bows.

That's rather a good point; the old ACs, and the lighter UACs, have basically been made obsolete by the march of progress in the game's universe, particularly the proliferation of things like DHS.

On that same note, though, I would love to see a new wave of autocannons that are meant to replace the old versions on the "modern" (i.e. 3150s and later) battlefield. There's certainly design space for new weapons in this category that can behave more competitively with energy weapons and missile systems.

It would, however, be a true nail in the coffin for the older AC designs, but that's kinda happened anyway. And they'd still be around in the Periphery.

[Cryhavok101]

I see Gauss tech as the future of ballistic design in BattleTech. Compare the HAG-20 to the clan LB 10-X to see what I mean. Eventually Gauss weapons will start firing warheads instead of just solid shot (like our current modern day experimental railguns are already trying to do).

Gauss weapons don't have explosive ammo, and despite the weapon itself being explosive, it is a lot less dangerous an explosion than a full ammo bin exploding. Gauss weapons are all long range weapons. Their only disadvantage is that they don't really have light caliber equivalents of AC-2s or -5s. A HAG-20 is a fantastic replacement for an LB-10X AC, but you can't really replace an AC-5 with it. On the other hand even the machine gun is outclassed by it's Gauss equivalent (AP Gauss). Personally I consider the light caliber LBXs as some of the best light anti-aircraft weapons in the game.

Now I have never used an silver bullet Gauss on the inner sphere side of things, so I can't speak to it's effectiveness, but to me it is clear that Gauss technology is the future of BattleTech's ballistic scene... and as I said before, I am okay with new tech obsoleting old tech.

Especially with the rise of retrotech. Militaries are plainly willing to use old tech still, as long as it can be made cheaply, and that is one things ACs should be good for is cheap production costs.

Also, an LB 5-X AC is, in my opinion, better at AA than an LRM 20. It's 5 potential hits does something more than any other weapon it's size can do (to airborne things anyway). The LB 2-X AC even has it's place as a decent AA weapon, since it can score as many hits as an SRM-2, but at some nicely staggering ranges. No laser, missile, or other ballistic weapon does quite what those two weapons can... unfortunately a certain armor type could potentially obsolete them anyway... and I would be okay with it, because that is what technological progress should look like.

[HobbesHurlbut]

Their only disadvantage is that they don't really have light caliber equivalents of AC-2s or -5s.

So....Light Gauss Rifle and Magshot Gauss Rifle don't exist for you?

[Sabelkatten]

So....Light Gauss Rifle and Magshot Gauss Rifle don't exist for you?

Not really comparable... The LGR is still 12 tons, only a little less than the standard GR's 15. The Magshot is more like a souped-up MG.

A "Gauss light AC" ought to be in the 5-10 ton span.

[Cryhavok101]

Not really comparable... The LGR is still 12 tons, only a little less than the standard GR's 15. The Magshot is more like a souped-up MG.

A "Gauss light AC" ought to be in the 5-10 ton span.

This. When your sizes jump from half a ton to twelve tons and then have a range of tonnages in the double digits, it tells me you are missing some lighter caliber sizes you could have but don't. Were gauss weapons going to be developed and replace AC's, I would say you need to fill in that massive gap.

[TigerShark]

House rules I've been using for ACs for the past few years in our online campaign:

(1) Ultra ACs don't jam.
(2) Standard ACs may use Rapid Fire rules. They jam on a roll of [3] and explode on a roll of [2].
(3) Rotary ACs do not check for jamming when being used in 2-shot mode; 3- or 4-shot jams on a [2]; 5- or 6- shot jams on a [3].
(4) Armor-Piercing, Flak, Incendiary are available for all eras.
(5) TacOps Expanded Critical Hits rule, giving the AC/20 and AC/10 a bit more punch.

[Col Toda]

With combined arms being very common in the game now people are looking at 1/3 to 2/3 of the combat units facing you should be combat vehicles with single heat sinks and no heat generated from ballistic weapons . Both light AC2 and 5s already have no minimum range so the only truly relevant complaint does not exist after 3068 '

[theagent]

House rules I've been using for ACs for the past few years in our online campaign:

(1) Ultra ACs don't jam.
(2) Standard ACs may use Rapid Fire rules. They jam on a roll of [3] and explode on a roll of [2].
(3) Rotary ACs do not check for jamming when being used in 2-shot mode; 3- or 4-shot jams on a [2]; 5- or 6- shot jams on a [3].
(4) Armor-Piercing, Flak, Incendiary are available for all eras.
(5) TacOps Expanded Critical Hits rule, giving the AC/20 and AC/10 a bit more punch.

• I've been debating this for some time.  However, I don't think it would work as a general rule replacement.  I think it works better as an "Improved" Ultra Autocannon.  Kind of like how the Heavy Gauss Rifle was reworked into the Improved Heavy Gauss Rifle:  very, very slight drop in range, slight drop in maximum damage but it keeps that damage through all range brackets, & it's just a little heavier.  I could maybe see an Improved Ultra Autocannon weighing 1 more ton than the standard versions, & that would allow it to drop the jamming rule.
• Already covered in Tactical Operations, p. 100, & is also available to MGs.  Not sure there's anything wrong with the optional rule as it currently stands, since standard ACs don't have the special firing circuitry/feed chambers or multiple barrels to allow for rapid-fire like Ultra & Rotary ACs.
• I'm on the fence on this one.  They haven't had the Rotary ACs around as long as the Ultras, so I have trouble seeing them finding a way to remove the jamming chances like that.  I could maybe see adding another ton to a Rotary AC to reduce its jamming chances.  But they already have a leg up on Ultra ACs, in that the pilot can actually clear the jam in the field.  That's something that even our real-world Gatling cannons can't do (or at least not the large-caliber aircraft versions).
• Incendiary & Flak seem to already be pretty readily available, unless you're really looking for some pre-BattleMech era action.  Incendiary LRMs were available in 2341 (TO p. 369), & Flak AC ammo was available in 2310 (TO p. 352).  I can maybe see a case for Armor-Piercing AC ammo, except that the standard AC ammo is already described as "high-explosive, armor-defeating" (TechManual, p. 207).  Remember, even the advanced armor of real-world vehicles like Abrams or Armata MBTs is nothing like BattleMech armor:  given the right ammo & firing angle, you can penetrate real-world tank armor more easily while still leaving a section relatively intact, whereas BattleTech armor pretty much resists penetration until its gone, unless specialized ammo is used (i.e. AP autocannon, tandem-charge SRM, etc.).  Where I think we might be missing out, though, is the use of specialized ammo for the Rifle (Cannon) from Tactical Operations.  Per the note at the bottom of page 338, they only use "standard" ammo.  However, these are the cannons that truly correspond to our real-world weapons (like the old M68 105mm or Rheinmetall 120mm tank cannons).  I could totally see Flak, Incendiary, & even Flechette, Caseless or Armor-Piercing ammo being developed for them (where else, after all, would Autocannon manufacturers get the idea to develop those ammo types for Autocannons in the first place?).
• Nothing wrong with that, although a) it's already a rule officially available, & b) since it's considered an optional rule, as long as everyone in your campaign agrees you're free to use it already.  I guess my only concern with it is regarding the damage.  Sure, it makes a shot from an AC/20 (or even a Gauss Rifle) more worrisome, but a hit from an AC/20 is actually no more likely to get a critical hit (+1 to your 2D6 roll means your actual results will range from 3-13; the chances of 3-8/9-10/11-12/13 match up identically with 2-7/8-9/10-11/12 from the old table, so you have the same chances for no criticals/1 critical/2 criticals/3 criticals) -- & actually, you lose the chance for the limb or head to be blown off (new table needs 15+, which will only happen if you have a +3 or better modifier to your roll, which means 16+ points on a single hit).  But, again, that also kind of makes sense, as only the most destructive weapons should have a chance of blowing them off (otherwise, you might have that situation where a Small Laser blows the arm off an Atlas...)

[theagent]

True, even with intro level tech an ML boat Hunchback conversion has more firepower and can blast away all day.

Not decidely so.  There's already a stock Medium Laser Boat Hunchback, the HBK-4P (one of the so-called "Swayback" models).  Technically, it has higher BV (1,138 vs. 1,041) for a slightly lower cost (3,377,875 vs. 3,437,875 C-Bills), so you get more bang for the buck & per ton.  But the actual capabilities aren't necessarily as great as you would think:

• Both the HBK-4G & HBK-4P have identical armor tonnage & armor coverage, so assuming the pounding is equal they can stand up to it equally.
• Both have the same movement profile (Walk 4/Run 6, no Jumping).  In a 1-on-1 fight, then, with equally-rated pilots (Gunnery 4/Piloting 5), unless the controlling player for 1 of the 'Mechs makes a really bad movement call, they're probably going to be circling & facing each other the entire fight.
• Both have a Small Laser in the head (3-hex range), & the Medium Lasers on both 'Mechs have the same range profile as the -4G's AC/20 (9-hex range).  Again, assuming equal Gunnery abilities, both Run, & each get the same TMM, each pilot has to close to his opponent's range to attack.
• Actual weapons load is where they differ.  As noted, both have a Small Laser, which (unless you want to close to 1 or 2 hexes) we can safely ignore.  The -4G has 2 Medium Lasers, & an AC/20 with 10 shots, with 13 heat sinks to cover everything.  The drops the AC/20 (all 16 tons, including ammo), for 6 more Medium Lasers...but is forced to add another 10 heat sinks.  As such, it only manages to add 10 points to its potential maximum damage (30% increase out to 3 hexes, 33.33% increase out to 9 hexes).  Assuming Gunnery 4, +2 for Running, & a +2 TMM for each one (movement, terrain, or a combination of the 2), then each one needs 8+ to hit at Short Range, 10+ to hit at Medium Range, & 12 to hit at Long Range.  Considering that's a 1-in-36 chance on each weapon at Long Range, I seriously doubt even the -4P pilot is going to want to stay out there.  We're probably looking at them staying at Medium Range, or possibly closing in to 3 hexes (Short for the AC & MLs) to really pound on each other.  With that kind of accuracy, the -4P pilot might reasonably expect at least 1 of his lasers will hit the target each turn, maybe even 2 (1/6 chance x 8 shots = 8/6 = 4/3 average chance that at least 1 laser will hit each round).  Doesn't sound too bad; 5 points here, 5 points there, that can add up on a Hunchback target.  The -4G pilot can also reasonably expect at least 1 shot to each turn...provided he fires everything (1/6 x 3 = 1/2 average chance), but even then he's looking at a lot of turns where nothing will probably hit.  He might take the occasional potshot with the AC/20, but might reserve it for a lucky break where he can close in.  Again, he may not have as many lasers hit, but 5 points here & there could still add up.
• The problem is that the HBK-4P doesn't have any "killer" weapons.  Unless he can manage to get behind the -4G pilot, or manage to roll a 2 on the Hit Location Table (a 1-in-36 chance), every section on the -4G will shrug off a Medium Laser hit.  Besides the rear torso sections, the Head is the most vulnerable, but it takes 2 Medium Laser hits before it takes internal damage, & 3 to be destroyed; as another 1-in-36 chance per successful shot, it's possible but not really probable.  All of the other sections on the -4G can take 3-4 laser hits (5 for the Center Torso) before they have to start worrying about internal damage & potential critical hits.  Now, sure, if you blow up an ammo bin, even with just 1 shot left, the -4G is going to be crippled at best, & destroyed at worst...but that's going to take a lot of shots.  In contrast, the -4G has that big, nasty AC/20.  Again, getting behind the -4P isn't going to be easy (as a single AC/20 shot to the back in any torso section will instantly destroy it; side torso hits means losing that arm & all but stripping the Center Torso's rear armor, while a Center Torso hit is an insta-kill), but a single AC/20 hit will completely strip the armor from a Leg, side Torso, or Arm (& do internal damage to the arm), leaving them open for further internal damage; even a Center Torso hit will only leave 6 points on that section.   Not to mention the possibility of an insta-kill with a Head hit.  And every AC/20 hit means the -4P pilot hopes he makes his PSR to stay upright...as a fall means the -4G pilot can easily close & pound him with an Alpha Strike.  And even though the -4P doesn't have ammo to explode, once it starts suffering critical hits it has to worry about losing all of those heat sinks (15 of the 23 are located outside of the engine, 7 in the Left Torso alone) & lasers (6 Mediums are in the Right Torso, so losing that section puts it in a really bad spot).
• The other problem is heat management.  Running all the time, without using the Small Laser the -4G will go up 2 on the heat scale if he fires the AC/20 & Mediums, but won't overheat if he sticks to the lasers (or only fires 1 Medium with the AC).  The -4P also leaves off firing the Small Laser...but if he fires all of his Mediums while Running, he goes up 3 on the heat scale.  I've run the numbers for different scenarios.  Suffice it to say, if their Small Lasers aren't used, & both keep Alpha Striking...at the point the -4P loses all of its mobility (-4 MP at 20 on the heat scale, it hits that on Turn 7) & has a +3 To-Hit modifier, the -4G is still at half movement (-2 MP = Walk 2/Run 3) & only has a +3 modifier.  The -4G pilot can take Turn 8 & leave off the AC/20 to close with the -4P, dropping him down to 9 on the heat scale (back up to Walk 3/Run 5 & down to +1 modifier).  The -4P pilot has the unenviable option of either only firing 3 Medium Lasers (dropping him down to 7 on the heat scale, so that he's also at Walk 3/Run 5 but has no To-Hit modifier)...or pound another Alpha Strike at his opponent & have to avoid Shutdown (this time at 8+) & leaving himself open to be pounded by the AC/20 next turn.
• Things are even worse if they get close enough to throw their Small Lasers into the mix.  After 5 rounds, the -4P is immobilized at 20 on the heat scale (& the +3 modifier); the -4G is still moving, but very slowly (Walk 1/Run 2), & still shooting better (+2 modifier)...except that, as his opponent went up on the heat scale & slowed down, he could have held off on an AC/20 shot or 2 to maintain mobility & targeting.  Being able to have a 1- or 2-hex movement edge on his opponent not only potentially gives him a better TMM to avoid being hit, but gives him a better chance to go for a backshot.
• In any case, if both pilots want to avoid heat buildup, the -4G pilot can alternate fire on his Medium Lasers -- or, more likely, save his AC/20 for when he has a really good shot on his opponent -- & have no heat worries at all.  The -4P pilot, on the other hand, is looking at always leaving a Medium Laser idle to avoid heat buildup.  It's one thing to not fire an ammo-dependent weapon when you have limited ammo; it's another to have to constantly not fire 1 of your weapons to avoid overheating (or worse, not fire two weapons -- 25% of your load -- to stay at 0 on the heat scale).

Honestly, if I was going to take a Hunchback variant with 3025/3039 tech, I'd pick one of the other models:
 -- the HBK-4H has the same armor, speed, & heat profile as the -4G, but it trades out the AC/20 for an AC/10 (still with 2 tons of ammo) & 2 more Medium Lasers.  That gives it a sweet spot at 10 hexes where its AC/10 is still at Medium Range, but the -4G can't hit it; even at 7-9 hexes, it still has better shots than the -4G.  Another sweet spot is at 4-5 hexes (Short for the AC/10, Medium for its lasers & for the -4G's AC/20).
 -- the HBK-4J is even nicer.  Same speed, same armor.  Heat profile is actually worse, probably due to the 3 extra Medium Lasers it has (with only 1 extra heat sink).  What makes it nice, though, are the twin LRM-10s (each with a ton of ammo).  The really nice sweet spot here is at 10-14 hexes:  Medium Range for your LRMs, but the -4G can't fire back.  The true sweet spot, however, is the usual LRM sweet spot:  7 hexes out.  Short Range for your LRMs (& not in Minimum yet), & you can always plink a few of your lasers, but the -4G is still at Long Range for its AC/20 & lasers.  He could still get a lucky shot in with the AC/20, but you're more likely to hit than he is.
 -- the HBK-4N isn't bad either.  You not only can outrange him with the twin LRM-5s, but you have an AC/5 with double his range, allowing you that nice 10-12 hex spot (Medium for you, nothing for him) or even 6-7 hexes (Short/Medium for the AC/5, slightly Minimum/Short for the LRMs, but Medium/Long for him).
 -- I would avoid the -4P (due to the heat management issues above).  For the same reason, I would avoid the -4SP (2 extra MLs, twin SRM-6 launchers).  Not only do you have the -4P's slightly worse heat curve & lack of range advantage, your average damage is only slightly better than his (36 vs. 30), you have even more of a shotgun effect (with your SRMs doing less damage to more locations), & with the higher chance of overheating you actually have to worry more about ammo explosions (plus, crap, both tons are in the Center Torso...that's just begging for a blowup).

[theagent]

So I don't derail the Great Wyrm MOTW article with a rant about how unconscionably bad autocannons are in battletech, I thought I would put forward some homebrew rules to make these things viable.  Maybe not amazing, and certainly no match for the cheesy glory that is clan energy weaponry, but at least good enough that I am comfortable with them.

The reason I'm currently uncomfortable with autocannons is because they break my suspension of disbelief.  Under the current rules, autocannons are basically so bad that either their representation vs. other weapons is drastically uncharitable, or all the clans, great houses and minor powers have had a centuries-long lapse of sanity in continuing to field these things.

Here are my beefs with autocannons:


-Autocannons have poor damage per tonne of ammunition compared to missiles.  Once you account for missile scattering, autocannons pull slightly ahead of LRMs, but they are still squarely behind SRMs.  Streak SRMs, of course, clobber autocannons in terms of efficiency (and everything else that isn't an energy weapon)

OK, let's start right there.  I'm assuming you're looking at max damage...which almost never happens in-game.  But since it also mirrors what happens when the ammo explodes, we can take a look at it:

• MRMs:  240 points per ton
• LRMs:  120 points per ton
• SRMs:  200 points (SRM-2/-4) or 180 points (SRM-6) per ton
• ACs:  100 points (Class 5/10/20) or 90 points (Class 2) per ton

If you mean "poor" because of the damage you take from an ammo explosion...believe me, you'll prefer "poor" any day.  But even with that, they're pretty much on par with LRMs.

Now, since you addressed missile scatter, we'll go ahead & deal with that.  First, I'm assuming we're dealing with standard autocannons (or possibly the later Light ACs), & avoiding the specialty Ultras, Rotaries, & LB-X variants; otherwise, we'd have to consider the Artemis IV, Narc-following, & other specialty missiles.  Missile scatter actually brings up an important note.  Missile launchers scatter their hits:  LRM/MRM volleys are resolved in 5-point damage groups, & SRMs all hit different locations.  Even Streaks hit different locations, they're just a binary solution launcher (either the launcher locks on & all missiles hit the target, or the launcher doesn't lock on & 0 missiles hit the target).  That means at best, an SRM launcher's attacks are the equivalent of an AC/2 shot, & an LRM/MRM damage group is equivalent to an AC/5 shot.  All the larger launchers do is give you more of those smaller hits, giving you a shotgun-style effect on the target.  ACs, however, just do single hits to their target; maybe not so impressive for the Class 2 or 5 versions, but an AC/10 will worry a Light 'Mech, & an AC/20 makes even a Heavy or Assault 'Mech think twice about getting in close.

This doesn't make any sense, either from a real-world engineering perspective or from a game balance perspective.  Compare the M456 105mm HEAT round from the mighty L7 tank cannon to an RPG-29, which is also 105mm.  The 105mm gun round is much faster, but also much smaller than the RPG-29.  On the other hand, high-velocity 105mm tank guns are way too heavy for infantry to carry around, but missile launchers are not.  So rocket propelled munitions are a trade-off; the ammunition is much bigger and heavier, but the launchers themselves are much lighter.  The reasons for this are fundamental to internal ballistics, and so unlikely to change in the future.  Battletech gets this halfway right, of course; the guns are heavier than the rocket launchers... but the ammo is effectively heavier too (less damage/tonne).  Why would anyone use these awful things?

Probably because the Autocannons are actually superior to the real-world guns you described?  Remember, BattleTech armor is not equivalent to the real-world armor used on tanks -- which, even on high-tech models like the Abrams, can still have an anti-tank round penetrate the armor before the entire armor on that section is vaporized.  That's more like the BAR armor used on Support Vehicles (which in-universe were "the" combat vehicles before Combat Vehicles were officially introduced, as shown by the "primitive" models in the various Technical Readouts).  Unless you manage to put BAR 10 armor on the Support Vehicle (an impossibility for Tech Level A units, equivalent to 19th- or early 20th-century vehicles; Tech Level B units can use it, but they need the Armored Chassis modification, & they only get 4 points per ton of armor, 1/4th the protection that BattleMech standard armor provides), you have to worry about penetrating hits even if your armor isn't depleted.  Heck, you could have a max-armor 100-ton TL B Tracked vehicle (204 total points of armor, with easily 50 points on the Front, 40 points per Side, 30 points Rear, & 44 points Turret), but with BAR 6 armor a Heavy Rifle (9 points) has a chance on every hit of punching through & inflicting a critical hit, let alone a Large Laser, AC/10, PPC, or Gauss Rifle.  That's more like real-world tank battles, where tanks are "killed" (or at least "mission-killed") because they take penetrating hits to critical systems, & unless that critical system is a fuel tank or ammo bin they're crippled-but-still-mostly-intact blocks of metal on the battlefield.

BattleMechs, OTOH, are different.  Aside from the very low chances for random critical hits (either by that 1-in-36 chance of rolling 2 on the Hit Location Table, or by using specialized ammo), critical hits can't happen until the armor in a section is completely gone.  Imagine if you could upgrade an Abrams with armor that functioned like that, & how truly difficult to take out it would be.

-Autocannons have poor damage output relative to tonnage.

This doesn't make sense from an in-universe perspective.  Most battles in the BT universe are fought at the end of lightyears-long logistical trains, and attacking forces are constrained by what they can cram into their dropships.  Surely generals and engineers would try to economize on tonnage, and try to use only weapons that give the most zap for the least weight?  Surely, after centuries of warfare spread over nearly all the worlds that man has ever colonized, someone would have realized that autocannons completely suck and they should be using almost anything else instead?

This depends on how you look at it.  First off, I think it's deceptive if we simply look at the weapon stats as-is, vs. the additional "support" equipment they require.  Yes, autocannons & missiles won't function if they don't have ammo, so we have to account for their ammo tonnage when we look at any kind of comparisons involving tonnage.  By the same token, however, all weapons, (especially) including energy weapons, need heat sinks to offset their heat.  Yes, yes, I know:  every BattleMech comes with 10 "free" heat sinks.  But very few 'Mech designs, especially those with a lot of weapon systems, & especially those with a lot of energy weapons (I'm looking at you, Clan 'Mechs), have only 10 heat sinks (single or double) in them.  And once your weapon heat exceeds 10, you're pretty much adding heat sinks every time you add another weapon system.  Now, I'm going to ignore the situation of Combat Vehicles -- aside from the fact that they don't need heat sinks for ACs & missiles, they also have that situation where ICE-powered units not only have to spend tonnage on their heat sinks for energy weapons, but they need power amplifiers for them as well.  So for this situation, we're going to look at it in the abstract, & go with the following requirements:
 -- for now, we'll ignore advanced technology like Ultra ACs, Pulse Lasers, ER Lasers/PPCs, LB-X cannons, Gauss Rifles, etc., sticking with Introductory tech.  We'll also ignore Machine Guns; they don't generate heat, & they have massive amounts of ammo per ton, so their results end up pretty skewed.
 -- For ammunition requirements, all weapons must have at least 10 shots each.  Aside from the AC/20 (2 tons), LRM-15 (2 tons), & LRM-20 (2 tons), all of the other weapons only need 1 ton of ammo.
 -- For heat purposes, every heat point generated by a weapon has to be offset by a heat sink.  Yes, this means that a PPC has to add in 10 heat sinks for its 10 heat points, while an AC/5 only adds 1 heat sink.  Note that, since we're not considering advanced weapons, we're also not considering double heat sinks.
 -- In addition to calculating the damage per ton, I'm also calculating the tons per critical slot.  This is because there's more than one way to measure efficiency.  Wanting to pack the most damage into your 'Mech is good, but sometimes you can find yourself running out of space in your 'Mech before you've run out of tonnage.  That's because some weapons are actually quite bulky (i.e. their tonnage-to-slot ratio is low), compared to other weapons.
 -- For the ballistic & energy weapons, we're using maximum damage.  For missiles, the first number is the average number (i.e. assuming a 7 is rolled for Cluster Hits), while the number in parenthesis assumes maximum damage; since that rarely happens (aside from the SRM-2, which needs an 8+, all the other stock missile launchers need an 11+ on the table to get max damage).

With those adjustments, this is what we end up with:
 -- AC/2:  8 tons, 3 critical slots; 0.250 damage/ton; 2.333 tons/critical slot
 -- AC/5:  10 tons, 6 critical slots; 0.500 damage/ton; 1.667 tons/critical slot
 -- AC/10:  16 tons, 11 critical slots; 0.625 damage/ton; 1.455 tons/critical slot
 -- AC/20:  23 tons, 13 critical slots; 0.870 damage/ton; 1.769 tons/critical slot
 -- PPC:  17 tons, 13 critical slots; 0.588 damage/ton; 1.308 tons/critical slot
 -- LL:  13 tons, 10 critical slots; 0.615 damage/ton; 1.300 tons/critical slot
 -- ML:  5 tons, 4 critical slots; 1.000 damage/ton; 1.250 tons/critical slot
 -- SL:  1.5 tons, 3 critical slots; 2.000 damage/ton; 0.500 tons/critical slot
 -- LRM-5:  5 tons, 4 critical slots; 0.600 (1.000) damage/ton; 1.250 tons/critical slot
 -- LRM-10:  10 tons, 7 critical slots; 0.600 (1.000) damage/ton; 1.429 tons/critical slot
 -- LRM-15:  14 tons, 10 critical slots; 0.643 (1.071) damage/ton; 1.400 tons/critical slot
 -- LRM-20:  18 tons, 13 critical slots; 0.667 (1.111) damage/ton; 1.385 tons/critical slot
 -- SRM-2:  4 tons, 4 critical slots; 0.500 (1.000) damage/ton; 1.000 tons/critical slot
 -- SRM-4:  6 tons, 5 critical slots; 0.667 (1.333) damage/ton; 1.200 tons/critical slot
 -- SRM-6:  8 tons, 7 critical slots; 1.000 (1.500) damage/ton; 1.143 tons/critical slot

We can then rank them on their efficiency with these numbers.  Although I provided the maximum damage figures for the missile launchers, I'll omit them for now because they seldom do their maximum damage (1 out of 12 times, on average).
Most efficient by damage/ton (average damage):

• Small Laser
• SRM-6
• Medium Laser (tie)
• AC/20
• LRM-20, SRM-4 (tie)

Least efficient by damage/ton (average damage):

• AC/2
• AC/5
• SRM-2 (tie)
• PPC
• LRM-5, LRM-10 (tie)

So, we had a couple of energy weapons in the Top 5, but we also had an Autocannon, the mighty AC/20.  And while the AC/2 & AC/5 topped the Bottom 5, we also saw the "mighty" PPC on that list (4th-worst).  And both the top & bottom had missile launchers in them.  More importantly, there was a much bigger gap in performance between #1 & #2 on the Top 5 list than there was between #1 & #5 on the Bottom 5 List.  In other words, if you're looking for the most bang for the tonnage in your design, you have options from all 3 categories (including options you may want to avoid).

On the other hand, efficient use of space spotlights where autocannons excel.  If you have a 'Mech that doesn't have a lot of tonnage available (i.e. a fast Light or Medium 'Mech), you probably will focus on energy weapons & missile launchers, because the weapons are individually light, & you may have such limited tonnage that you can get by with those 10 "free" heat sinks (i.e. like the STG-3R Stinger, which needs no extra heat sinks to jump & fire its Medium Laser & MG...at least until it takes an AC/10 or PPC hit to a leg, or especially a Large Laser to the head...).  But if you have a Heavy or Assault 'Mech, it's a lot harder to build a Medium Laser "Boat", or even a Large Laser "Boat", without starting to worry about space.  On the other hand, slap in an autocannon, & you have the space left to pad it with some Medium or Small Lasers as backups.

-Autocannons are significantly less flexible than missiles.

This is a pure game balance perspective.  A rocket motor offers much more gradual acceleration than the barrel of a gun, so it makes sense that more sophisticated and delicate electronics could be stuffed into the nose of a missile than into the shell of an autocannon.  But if a weapon is basically bad, but still commonly fielded by almost everyone, I would reasonably expect it to do something cool on the side to balance out its lack of obvious merit.

Can't say I necessarily agree here...unless you mean by "flexible" their ability to scatter & simultaneously spread their damage all over a 'Mech, instead of dealing the damage to a single spot.  With an energy or ballistic weapon (barring cluster rounds), each shot does 100% of its damage to a single location.  That's why the AC/20 (& advanced-tech items like the Gauss & Heavy Gauss Rifles, or the Clan's ER PPC & Heavy Laser) have a built-in boost on their BV:  if you can roll boxcars on your Hit Location roll, a single shot will wipe out the Head of the 'Mech.

And sometimes it's nice to be able to have the extra oomph behind a single devastating blow.  I know the Hunchback IIC was mentioned in passing

[snip]

Sorry, it's cutting off my response, so I'll have to post it in parts.

[theagent]

So with all that in mind, here are my optional autocannon rules.  They're intended to be used all at once, but obviously you can pick and  choose if you think that wiser.  They're also intended to keep existing designs legal and require minimal changes to the rules sheets.  Finally, they're intended to be as simple as possible so as not to slow down gameplay.  Obviously, the use of these rules will distort the battle value of any unit that has an autocannon.

Two-mode Fuse for Standard Rounds

Autocannon "standard" ammunition is actually a marvel of miniaturized fusing technology.  Variable-delay fusing existed in the mid 20th century, but the manufacturing technology that could transform crude, hand-adjusted fuses into induction-timed, proximity fused, mass produced munitions that were ubiquitous down to the lowly class-2 autocannons took a little more time.  Essentially, autocannons are a hybrid HEAT/light armor piercing warhead with an electronically programmed fuse that can attack targets in two different ways.

Autocannon shells contain a forward-facing proximity sensor that can trigger their shaped-charge anti-armor warheads a few fractions of a second before impact.  This gives optimal standoff and implosion geometry to get the most performance possible out of the warhead.  Autocannon shells also have a light armor piercing cap internally and an all-aspect delayed impact fuse.  If required, the proximity sensor can be switched off and the shells programmed to explode a few fractions of a second after they smash into something.  This mode is devastating to static structures like buildings and the internal structure of mechs, although it does a poor job of penetrating military-grade armor.

The standard mode is with the proximity fuse on, and in this mode all "standard" autocannon munitions (for ACs, LBX, RACs, UACs, etc) behave as normal.  In delayed-fuse mode, the autocannon will do double damage to all buildings and all internal structure except for reinforced-type internal structure.  In delayed-fuse mode the autocannon will do half damage to armor of all types except for armor with a BAR of less than 10, exclusive.  The player attacking with the autocannon must decide which shell fusing mode they are using when they make the attack (the electronic fuse is set in the autocannon, the shells aren't smart enough to determine what they're about to hit).

Specialty ammunition types do not have a delayed-fuse mode.

I do like this optional rule.  And, at least for some specialty ammo, I can see why it wouldn't apply.  Flak & Armor-Piercing ammo probably already have specialty fuzes in them, so it makes sense for them not to have them.  And the same thing with cluster rounds for LB-X cannons.  Caseless ammo, though, is just standard shells where the propellant is built around the round instead of having a separate shell casing (combustible or not).  It just lets you have extra rounds per ton, it doesn't give you any damage adjustments, doesn't have any special attack effects, or give you any extra range.  So I could see caseless ammo being able to have a delayed-fuse mode...& maybe slug rounds for LB-X cannons, as well as the rounds for Ultras.

Increased Damage Against Battle Armor

Class-2 autocannons of all types do 4 damage against battle armor when firing standard ammunition, based on whatever rationale bearhunter ACs do bonus damage to BA.  Battle armor resists big hits well, but not lots of little hits that above some threshold.  Or something.  Class-5 autocannons of all types do 7 damage against battle armor while protomech autocannon-4s do 6 against BA.

This increased damage does not apply when firing any sort of specialty ammunition.

Well, maybe because the Bearhunter, even though it's called a "Superheavy AC", is actually more like a tri-barrel MG that's way too heavy, way too powerful in recoil, & is actually designed as an anti-infantry weapon...vs. standard ACs & even ProtoMech ACs, which are designed to be anti-'Mech (including anti-ProtoMech), & anti-Vehicle?  Note the discussion here:  http://bg.battletech.com/forums/index.php/topic,16511.0.html

Since the Bearhunter doesn't seem to do extra damage against Battle Armor (unless I'm missing something, since the table in Total Warfare on p. 217 talks about conventional infantry taking extra damage from MGs, Flamers, & the like), I'm not sure we really need standard Autocannons to do extra damage against battle armor.

Increased Ammunition Per Tonne

All standard autocannons have 140 damage per tonne of ammunition, so that's 70 rounds for -2s, 70 rounds for -5s, et cetera.  Hyper-velocity autocannons are 80 damage per tonne of ammunition, so 40 for -2s, 4 for -20s, et cetera.  Caseless autocannons have 200 damage per tonne of ammo.  Protomech autocannons go up to a whopping 160 damage per tonne because (mutters something about superior clan technology, composite case designs, piezometric ceilings and efficiency) it would just be too hard to increase those by anything that isn't an integer since they pay per kilogram.

This situates autocannons between LRMs and SRMs for ammunition efficiency, enough that they wouldn't obviously be failing to pull their weight in centuries of campaigns' op-evals.

Optionally you can bump up gauss rifle ammo per tonne if you think gauss rifles should be inherently more ammo efficient than autocannons.  Also, optionally, you can have all ammunition bins perform as though they have CASE, all CASE bins perform as though they have CASE II, and have all CASE II bins, and CASE II also prevents pilot damage from ammo explosions.  The current ammo explosion rules penalize ammo weapons pretty heavily, and don't make very much sense.  Isolated ammunition storage was pretty much a solved problem in the 1970s with the M1 Abrams.  Why would things get so much worse in the 31st Century?

A nice house rule, but I'm not sure it's really needed.  Missiles (or at least SRMs) may pack in a lot more damage per ton, but they seem to suffer from accuracy issues.  LRMs & SRMs need their guidance packages to even approach the accuracy of ballistic weapons, & even then they tend to scatter & not do their full damage.  MRMs technically function just like autocannons as a "point-and-shoot" weapon, but have accuracy issues (not only do they scatter, but they have that +1 modifier and those weird range brackets).  But hey, if someone likes it, that's fine with me.

Autocannon Failures

Ultra autocannon jams, standard autocannons using rapid-fire mode rules, and ammunition-related mishaps in caseless and hyper velocity autocannons can be un-jammed per rotary autocannon rules.  Does it make any sense to you that a military would field weapons that have a 1/36 chance of bricking themselves as bread and butter for centuries?  It didn't make any sense to me either.  Caseless and hyper velocity are likewise so dangerously unreliable that they would obviously never leave the test stands, much less see limited production.  Also, I thought it made more sense to consolidate jamming/failure rules on the various flavors of autocannon rather than have several different, and more punitive ones.  The game gets slightly more streamlined, and an underperforming weapon category gets some love, win/win.

I see this as more of a failure to develop "improved" versions (see my prior post about that).  I agree, though; the Lyrans managed after only a few years to fix their Heavy Gauss Rifle, you'd think someone would have fixed the Ultra AC jamming circuitry.

Caseless & HVACs, however, I think may have to be left as-is.  For HVACs, they're not only considered very new, but it's because they're using volatile propellants (which give them those nice range extensions).  Kind of like how you have real-world "base-bleed" & Rocket-Assisted Projectile rounds for artillery units; I'm sure they're designed to be as safe as possible, but you're talking about exposed propellant (base-bleed) or super-giant/super-powerful fireworks (RAP) that can receive extra care because they're being loaded individually (generally) by hand.  In a fully automatic feed system, especially in systems where environmental heat can cook off regular rounds, I'm not sure you can eliminate those issues.  And I know there have been a few real-world caseless rifles (i.e. Heckler & Koch's G11), but for the most part I don't remember them being as popular or successful as standard cartridge-fed weapons.  Not sure if that was because they had feed issues or not... but if so, it might be a good reason to keep it (plus, you're trading the small chance of a jam for having extra ammo).

Ultra Autocannon Hyperburst

In the late 20th Century, Soviet small arms engineers began work on a radical type of infantry rifle that combined an internally recoiling barrel with an extremely fast cycling burst mechanism in order to fire bursts that did not have their dispersion affected by the rifle's recoil.  This work culminated in the AN-94 Abakan rifle, which saw limited issue into the early 21st Century.

Ultra Autocannons are that, but way bigger.  The Soviet AN-94 had a mixed reputation for mass-produce-ability and reliability, so it obviously took some time before engineers were confident enough to attempt to scale up their design.  Many a prototype ultra autocannon tore itself to pieces on the test range before the design was ready for mass production.

When firing in two-shot mode and at a single target (i.e. not using the multiple targets rules from TO), the to-hit roll is also a margin-of-success roll.  If the to-hit roll is greater than the target number by 2 for UAC-2s, 3 for UAC-5s, 4 for UAC-10 and 5 for UAC-20s, then skip the cluster hits roll, both shots strike the same location.  Roll for location normally.  If the to-hit roll is greater than the target number, but not by the margins listed above, the number of shots that hit and the locations where they hit are resolved normally.

Not a bad house rule, really like this one.

Counter-Defilade Mode for LBX

If a unit is obscured by cover that is the same height as the unit being obscured (e.g. a battlemech is hiding behind cover 2 levels tall), and the unit obscured is immediately adjacent to the cover it is obscured from its attacker by, LBX cluster munitions may be used to attack it per LRM indirect fire rules if there is a spotter.  If the unit is obscured from its attacker by cover that is taller than the unit being obscured, or if it is hiding around a corner, then it cannot be attacked with LBX cluster munitions.  The proximity sensor fuse time gate is "smart" but it isn't brilliant.  Attempting to use the fuse settings to get the munition to detonate just behind a target when attacking it from the front is similarly out of the question.

LBX cluster munitions are essentially miniaturized, sensor-fused cluster bombs shot out of a cannon.  Again, they are nothing that an early 21st century commander would be unfamiliar with, but great strides in manufacturing technology allowed these advanced munitions to be mass-manufactured and distributed out of the barrels of cannons like so much candy out of a pinata.  Each cluster carrier has a proximity sensor that can be time-gated to ignore cover for a certain distance, and then go active once past a certain distance.

Seems like a reasonable rule.  One question, though:  any particular reason for why you can't indirect fire when the target is behind higher cover?  LRMs seem to have no problem with it (as apparently their trajectory is also designed to drop over the covering the terrain but still hit the target as normal), so I'm not quite seeing why the cluster round would have trouble.  Also, does the normal -1 modifier still apply for using the cluster round, or is it eliminated through the use of indirect fire?  Otherwise, it would actually turn out to be more accurate than LRM fire (with the -1 counteracting the +1 indirect fire modifier).

New Ammo Types

The standard autocannon's feed system is admirably omnivorous, being able to load, fire, and extract a number of non-standard ammunition types that the original designers could never have foreseen.  LBX autocannons use a high-low pressure system that prevents damage to the sophisticated electronics in the submunitions of their cluster shells, and as a result their ammunition is completely incompatible with standard autocannons, and vice versa.  Ultra autocannons use counter-rotating revolving cylinders that also reciprocate and fire binary ammunition that is wildly incompatible with anything exotic.  Ultra autocannons are fidgety enough with the ammunition carefully tailored for them, sticking anything strange in their feed systems is totally out of the question!  There was initial optimism at NAIS that rotary autocannons would prove compatible with a wide array of specialty munitions, but qualification trials have long since dashed that hope.  The specialty munitions simply were not made robust enough to survive the high speed of the feed systems in RACs.  Hyper-velocity autocannons and caseless autocannons have proven too rare to be worth furnishing with compatible, specialty ammunition although such ammunition could easily be developed if there were any demand for it.

But bog-standard autocannons proved able to accommodate several new ammunition types, even after the initial introduction of novel types in the late 31st century.

GLATGM ammo:  Taking a page from Soviet tank designs of the late 20th century, designers realized that firing a missile (specifically, a Gun Launched Anti-Tank Guided Missile) out of a gun might be useful.  Furthermore, the missile could be broken up into two parts that would be snap-assembled in the loading tray of the autocannon before being chambered in the gun (this is exactly how Russian gun-launched missiles work).  The designers also realized that only the AC-20 had a wide enough bore to accommodate a worthwhile missile.

GLATGM ammo is for standard AC-20s only.  GLATGM ammo is exactly the same as a thunderbolt-10 in terms of range and shots per ton, but it develops the same 7 heat as a standard AC-20 shot.  For campaign purposes, it should not be considered interchangeable with thunderbolt-10 ammunition; the missiles have been designed from the ground up to work in autocannon feed systems.

Did the Soviets actually end up being more successful with it than the USA?  The old M551 Sheridan (as well as the M60A2 version of the Patton) had a 152mm short-barrel gun that fired conventional rounds (HE or HESH, I believe) as well as the Shillelagh ATGM.  They wanted their air-dropped light tank to have some heavier firepower.  IIRC, though, the missiles had problems with the guidance systems being unable to handle the shock of being fired from the cannon reliably.

In any case, I suppose it's a potentially nice option for extending your range, but the damage drop (& usual problems with an AC/20's ammunition numbers) kind of seem a bit negative to me.

OTOH...if it was the equivalent of a T-Bolt 15 (with the same 4 shots/ton), or added an option for the AC/10 to take a T-Bolt 5 variant (limited to 10 shots/ton), that might make it more attractive.

HESH ammo  HESH (High Explosive Squash Head) consists of a relatively thin-walled, insensitive explosive that deforms and flattens against the target.  Once it has spread out an achieved maximum contact area with the target, it detonates, creating a shock wave inside the target that can cause spall to rip off of the inside of the target's armor plate.  This effect can cause "scabbing" off of the inside of a target even if the HESH round doesn't penetrate.  HESH is also particularly devastating against walls.

HESH ammunition was largely abandoned in the early 21st century due to the proliferation of early composite armors.  However, the development of ultra-brissant, high-density explosives in later centuries made the concept viable once again.

HESH ammunition is for all standard and light autocannons.  HESH ammunition does 2 points less damage than normal, down to a minimum of 1.  HESH ammunition does double damage to buildings (so, 2, 6, 16, 36).  HESH ammunition has a +1 to-hit modifier.  HESH does half damage (round down) to battle armor and infantry.  If a HESH round hits an armored target, but does not remove all of the armor on hitting it, and the amount of armor remaining on the target is equal to or less than the amount of damage the HESH round inflicted, roll on the determining critical hits table with a -1 modifier.  If there are more points of armor remaining than the HESH round inflicted damage, there is no effect.  If the HESH round removes all the armor and damages the internal structure, critical hits are resolved normally.
Thoughts?

Nice idea.  Perhaps a bit complicated, especially since it seems to be combining the effects of different ammo types.  Maybe something like this?
 -- Does 50% more damage (round up) against buildings, but half damage (round up) against other targets (including infantry & battle armor0
 -- +1 modifier (due to the need for the shell to "stick" to the target to work properly)
 -- Treat as Armor-Piercing rounds against Vehicles & 'Mechs

That lets you use references to existing rules, & makes the math a little easier (think the only loss is a little bit of building damage for the AC/10 & AC/20, but it's not a whole lot).

In summary... I like the ammo options, & I like some of the other rules.  I think you might be underestimating standard autocannons a bit in comparison to the other weapon types, but I agree that there is some room for improvement.

[TigerShark]

• I've been debating this for some time.  However, I don't think it would work as a general rule replacement.  I think it works better as an "Improved" Ultra Autocannon.  Kind of like how the Heavy Gauss Rifle was reworked into the Improved Heavy Gauss Rifle:  very, very slight drop in range, slight drop in maximum damage but it keeps that damage through all range brackets, & it's just a little heavier.  I could maybe see an Improved Ultra Autocannon weighing 1 more ton than the standard versions, & that would allow it to drop the jamming rule.[/l][/l]

Don't need one.
Prototype Ultra AC/X: Jams on a roll of "2" when in Ultra mode.Production Ultra AC/X: Does not jam.
[/list]

[theagent]

Don't need one.
Prototype Ultra AC/X: Jams on a roll of "2" when in Ultra mode.Production Ultra AC/X: Does not jam.
[/list]

I've been thinking long & hard about this.

On the one hand, I think Ultras have been around for long enough that something needs to be done to allow for the jamming to go away.  I have to agree that after centuries of development, no one -- Clans, ComStar/Word of Blake, NAIS, etc. -- hasn't thought of some way to compensate for the problem of throwing 2 shells down the barrel with a single trigger.

On the other hand, I'm really reluctant to simply say, "after year X they're no longer subject to that rule".  There are a number of reasons I thought of:

• We already have canon examples of prototypes for both the Ultra autocannons & standard autocannons, from multiple sources (Interstellar Operations is just the newest one, but the XTRO: Primitives line also talks about the primitive AC/10 & AC/20, while Historical: War of 3039 first introduced the UAC-P prototype for the Ultra AC/5).  Sure, the prototype standard ACs have that same "jam on a 2 that the production Ultras get...but they also have less ammo than normal (75% per ton), while Ultras have the normal amount per ton (they just need more ammo to be "legal").  The UAC-P is more likely to jam in double-tap mode (4 or less) & can even jam on a 2 in single-shot mode, but aside from an extra slot it's identical at least to the production model.  Switching over & saying that the "production" Ultras are actually "prototypes" makes the situation kind of messy.
• We also have an example of at least 1 weapon where the initial production model was, in fact, improved:  the Heavy Gauss Rifle.  The improved model drops the maximum damage slightly, but in return no longer has the damage drop-off over range; to compensate for that, though, they had to make it 2 tons heavier & increase the cost by 200,000 C-Bills, plus it lost a hex from Medium & Long range.
• Finally, every bit of advanced technology in BattleTech, by design, has a counterbalancing downside to it.  Want to save tonnage by using Endo Steel, Composite, or Endo-Composite for your structure?  You're either more vulnerable to internal damage (Composite) or lose some available slots for other equipment.  Same thing happens with the various armor types, either needing more tonnage to maximize it (Hardened), additional equipment to make it work (Stealth), or lose available slots, & a lot of the other construction equipment.  Weapons have similar issues:  ER energy weapons generate a lot more heat, LB-X cannons are more bulky [although I'm not sure why the LB 10-X isn't; it's the only LB-X variant that uses less slots than the original, it really should take 8 slots], Pulse Lasers need more tonnage, etc.  Ultras gain a slight range edge (Medium/Long brackets) & can fire twice, but weigh an extra ton & have that 1-in-36 chance of jamming. 

I'd have no problem with an Improved Ultra AC weighing an extra ton (maybe 2 tons for the Ultra AC/20), & costing extra (standard seems to be Ultra AC = 1.6 times the cost of the base AC, so maybe the Improved Ultra AC = 2 times the cost) in order to get rid of the "Jams on a 2" rule.  But I'm really leery of just putting a timer switch on it...

[TigerShark]

Unfortunately, many factors just aren't accounted for in BattleValue.

• Heat: 0 damage and 10 heat? Same BV as 10 damage and 15 heat.
• Jamming: 10 damage per shot, 2 shots max (Ultra AC/10). Same BV whether it jams or not.
• Tonnage: Whether it's 100 tons or 10 tons, it doesn't matter. Tonnage doesn't count.
• MASC Failure: A MASC system that propels a unit to 8 MP (4/6[8]) gives the unit the same BV as a natural 8 (5/8).
• Ammunition: A weapon with 0 shots of ammo is the same BV as one with 100 shots.

A lot of these are "fluffy" qualities. Tonnage doesn't factor into usefulness on the field of battle. So it stands to reason that it shouldn't be counted in a BV calculation. Heat efficiency? That's calculated with the heat sinks vs. weapons, so we can leave that alone as well. But there are two things that make no sense: MASC Failure and Jamming.
MASC Failure makes a unit that's prone to failure and one that isn't a comparable BV. Take the Hermes HER-1S, for example:

9/14 speed, 716 BV.
7/11(14) speed, 716 BV.

Both of these are capable of generating the exact, same TH mod. Both move the exact, same number of hexes. Both are the exact, same BV. But only one of them has to check EVERY TURN they utilize the MP they've already paid for in BV. That's a SEVERE drawback and it needs to be accounted for. Just because MASC is cheaper in tonnage doesn't mean that's "balanced." As we've stated before, tonnage doesn't reflect BV and isn't a factor. A Clan LB-10X is the SAME BV as an IS LB-10X, despite being the same heat, range, and damage.

So that's one reason I've had to house rule that MASC gets a free turn of success. 0, 3, 5, 7, etc. It already paid for its speed boost in BV -- It shouldn't be saddled with jamming if that isn't accounted for as a BV discount.

Same goes for jamming. A weapon that fires 2 rounds/turn and doesn't jam shouldn't be the same BV as one that does jam. That's broken. And that's how the current calculation is. (http://www.heavymetalpro.com/bv_calc.htm) Until that's fixed, I don't think any AC, Rotary or Ultra, should jam during a game. Not as long as they're being calculated as doing their full damage each turn. I agree that jamming is a fine thing and could be fun to include. But they'd have to say "this weapon gets a 30% discount on the final BV of the weapon if it jams during use," or something to that effect. Then at least you wouldn't be paying 100% for a weapon that turns into a useless hunk of metal after a few turns while your opponent's laser boat is firing unlimited.

[Cryhavok101]

Unfortunately, many factors just aren't accounted for in BattleValue.

• Tonnage: Whether it's 100 tons or 10 tons, it doesn't matter. Tonnage doesn't count.

Tonnage is accounted for indirectly. Using Clan tech vs Inner Sphere tech for an example, the lighter weight of clan tech means you are paying the battlevalue of all the extra gear you fit on because of the lower weight. A clan mech for example can put two LRM racks for every one an inner sphere mech can... and the battlevalue will show it.

[Sabelkatten]

BV also does count ammo, even if it does it extremely badly (including the obvious nonsense of a weapon w/o ammo still having most of its BV).

But most designs do have ammo for their weapons, so the real sillyness is that ammo BV varies with the weapon it's loaded in. Even if it's the same ammo! The most obvious is that a LRM20 with 12 rounds is ~15% more expensive than 4xLRM5 with 12 rounds each...

[Hptm. Streiger]

Well lots of BV issues (like the LRM5 vs LRM20) is based on rounding

Another interesting aspect is that different advanced rules can have some effect on weapons
Take for example the glancing/direct blow, extreme range and alternating cluster/energy damage rules, or alternated crits

Its obvious that weapons like MRM will deal even less damage, were weapons like a VSPL would deal havoc at close range.
With TW rules a Cluster weapon like the LB20X might need some correction for the advanced propability to deal critical damage or headshots - with the TO critical hits however the Cluster part would only have higher chances to deliver headshots.... and don't forget that at some point the usage of Ferro Lammelor would do you cluster damage nil and void

of course there are possibility to circumvent those caveats -

LBX -> fire always cluster rounds always get the -1 to hit... for example class 10 one solid chunk of 6 dmg add +1 on the "roll for critical damage")
LB1X; LB3X; LB6X; LB13X
UAC -> fire always two tap add 50% total damage divide by two (so two clusters of damage)
UAC4(2x2);UAC8(2x4);UAC16(2x8);UAC30(2x15) - of course - reduce ammo by 60%

same for rotarys - but here you could combine cluster with uac style
RAC2  9dmg - (3x3) 11 shots per ton
RAC5 -1to 18dmg (3x6)  5 shots per ton

this would turn std auto cannons in more efficient guns

[TigerShark]

Tonnage is accounted for indirectly. Using Clan tech vs Inner Sphere tech for an example, the lighter weight of clan tech means you are paying the battlevalue of all the extra gear you fit on because of the lower weight. A clan mech for example can put two LRM racks for every one an inner sphere mech can... and the battlevalue will show it.

By this same logic, Endo Steel would have a higher BV than a normal structure. Which it doesn't. Any piece of equipment you put on has its own BV, so you don't need to assign one to a weapon based on its tonnage. A weapon's weight is not accounted for in the actual BV calculation.

[TigerShark]

BV also does count ammo, even if it does it extremely badly (including the obvious nonsense of a weapon w/o ammo still having most of its BV).

But most designs do have ammo for their weapons, so the real sillyness is that ammo BV varies with the weapon it's loaded in. Even if it's the same ammo! The most obvious is that a LRM20 with 12 rounds is ~15% more expensive than 4xLRM5 with 12 rounds each...

That's really a problem. A Gauss Rifle (320 BV) with 2 tons of ammo (40 each, or 80 BV) is only 12 BV less than a Clan ER PPC (412 BV). So... wait. A weapon that explodes when critted and can only fire for 16 rounds is the same BV as something that can fire forever and never explodes?  :o

Even sillier is the fact that a Gauss Rifle with 8 shots of ammo (360 BV) is 95 BV more than a Clan LPL. So over the course of, say, 15 rounds, the Gauss Rifle's maximum damage is 120, while the LPL's is 150. 20 rounds? 120 vs. 200.

ANYTHING carrying ammo should have half of the BV carried by its ammunition, and not the gun, which is useless without ammo.

i.e.: AC/10 is currently 123 BV and the ammo is 15 BV per ton. A fully-functional AC/10 with 20 rounds (i.e.: more than 12 shots) would then be 153 BV. For a fair calculation, the gun itself should be half (76 BV) and the ammo the other half (76 BV / 2 = 38 BV per ton). So an AC/10 that's under-supplied with only a single ton of ammo would be 114 BV, while the fully supplied, 20-shot AC/10 would be 152 BV.

To bring this back to "how to make ACs not suck?", a big problem is in how they're rated for Battle Value. They're over-valued currently, and especially so when their ammo supply keeps them out of a game after X rounds. Which is usually less than 12. (Just an estimate based on experience. The LRM-10's 12 shots seems ideal for an average-length engagement. IMO.)

[Cryhavok101]

By this same logic, Endo Steel would have a higher BV than a normal structure. Which it doesn't. Any piece of equipment you put on has its own BV, so you don't need to assign one to a weapon based on its tonnage. A weapon's weight is not accounted for in the actual BV calculation.

A mech with endosteel will typically have higher BV than a mech without it, because it has more gear due to more available tonnage. The end result of the battlevalue calculation shows this, even without individual component BVs accounting for the weight of that component.

[Sabelkatten]

BV does have a modifier for "explosive components", so you do get a break for packing ammo. And ACs are actually one of the worst abusers of the BV system. More specifically, AC/2s!

5 AC/2s with a ton of precision ammo each are roughly equivalent to a clan LPL (same total damage, longer range, less accurate against slow targets), but only 210 BV compared to 265! The only things more broken are MMLs and ATMs...

The most practical and close to correct way to handle ammo BV would be to have a list of BVs for each weapon depending on ammo supply. I.e the LRM20 could look something like this:

Ammo:   0   1-3   4-9   10-15   16+
BV:      0   50   110   180      240

[TigerShark]

A mech with endosteel will typically have higher BV than a mech without it, because it has more gear due to more available tonnage. The end result of the battlevalue calculation shows this, even without individual component BVs accounting for the weight of that component.

So does your theory account for smaller engines as well? i.e.: a 3/5 Mech at 70 tons has more tonnage free than a 4/6, so they should always be higher BV?

[TigerShark]

BV does have a modifier for "explosive components", so you do get a break for packing ammo. And ACs are actually one of the worst abusers of the BV system. More specifically, AC/2s!

5 AC/2s with a ton of precision ammo each are roughly equivalent to a clan LPL (same total damage, longer range, less accurate against slow targets), but only 210 BV compared to 265! The only things more broken are MMLs and ATMs...

The most practical and close to correct way to handle ammo BV would be to have a list of BVs for each weapon depending on ammo supply. I.e the LRM20 could look something like this:

Ammo:   0   1-3   4-9   10-15   16+
BV:      0   50   110   180      240

It doesn't do the same damage, since it's not an "all-or-nothing" scenario. i.e.: 5 AC/2s don't all hit every turn. While the LPL does do 100% of its damage with every hit. Also, Precision ammo only gives a -2 if your opponent generates a +2 or better. Clan LPL does this even when you stand still. And has no minimum range.

[Cryhavok101]

So does your theory account for smaller engines as well? i.e.: a 3/5 Mech at 70 tons has more tonnage free than a 4/6, so they should always be higher BV?

Higher speeds often offset it. Since there are a lot of factors. A better example would be a standard engine vs an XL engine, both the same rate. The one with the XL engine will (note the use of this word) probably have a higher BV. I say probably, because it also depends on what equipment they fill that weight with.

Look at it this way:
Battlevalue is a rating about a unit's combat performance, weight has nothing to do with that. The only effect the weight of any one item has on the battle is how many other things you can carry as well. That is directly factored into the end result of the BV calculations by adding all of those other things' battle values in as well. That is why clan machines almost universally have a higher BV than equivalent sized Inner Sphere machines.

Example:
CPLT-C1 BV2=1,399
Mad Dog Prime BV2=2,351

*numbers pulled from sarna.net

Nearly twice the BV2 on the mad dog, because it has launchers that weigh half as much, and numerous other weight saving things, so it can boost it's performance in nearly every other category, while filling the same role, in a similar manner even. However, going by BV2 alone, the Inner Sphere could field nearly 2 catapults for every one Mad Dog.

[theagent]

Unfortunately, many factors just aren't accounted for in BattleValue.

• Heat: 0 damage and 10 heat? Same BV as 10 damage and 15 heat.
• Jamming: 10 damage per shot, 2 shots max (Ultra AC/10). Same BV whether it jams or not.
• Tonnage: Whether it's 100 tons or 10 tons, it doesn't matter. Tonnage doesn't count.
• MASC Failure: A MASC system that propels a unit to 8 MP (4/6[8]) gives the unit the same BV as a natural 8 (5/8).
• Ammunition: A weapon with 0 shots of ammo is the same BV as one with 100 shots.

A lot of these are "fluffy" qualities. Tonnage doesn't factor into usefulness on the field of battle. So it stands to reason that it shouldn't be counted in a BV calculation. Heat efficiency? That's calculated with the heat sinks vs. weapons, so we can leave that alone as well. But there are two things that make no sense: MASC Failure and Jamming.

No, tonnage doesn't directly figure in.  It's more indirect, based on the overall tonnage you had available & how much you used for other equipment.  Same with heat:  using less-heat-intensive weapons means you don't have the design decision of either juggling weapons or having to "waste" tonnage & space on additional heat sinks, even if you're not trying to min/max the BV calculations.

MASC Failure makes a unit that's prone to failure and one that isn't a comparable BV. Take the Hermes HER-1S, for example:

9/14 speed, 716 BV.
7/11(14) speed, 716 BV.

Both of these are capable of generating the exact, same TH mod. Both move the exact, same number of hexes. Both are the exact, same BV. But only one of them has to check EVERY TURN they utilize the MP they've already paid for in BV. That's a SEVERE drawback and it needs to be accounted for. Just because MASC is cheaper in tonnage doesn't mean that's "balanced." As we've stated before, tonnage doesn't reflect BV and isn't a factor. A Clan LB-10X is the SAME BV as an IS LB-10X, despite being the same heat, range, and damage.

I'm having trouble finding that 2nd variant.  Do you mean the HER-3S1?  It's the closest I could find, but it's not a 7/11[14] design, it's a 9/14[18] design.  It has 726 BV instead of 716, but the change is so small because the extra boost from MASC is offset by the drastic loss in armor protection (down from 89 points to 44 points). 

It's almost kind of like a nitro boost for your 'Mech, or the in-universe Supercharger:  good for short bursts of speed, but continued use runs an ever-increasing risk of damaging the legs.  And at least they've updated the result of a MASC failure -- per the old TRO: 2750 & TRO: 3050, MASC failure meant both legs were immobilized for the rest of the game (probably a GM's call whether the -4 "immobile target" would apply to anyone attempting to fire at you).  At least with the Total Warfare rules, that would only happen if both critical hits were Hip Actuator hits (you might be lucky enough to make it out with just 2 Foot Actuator hits, or even better in some designs you might just lose a Heat Sink or Jump Jet instead).

So that's one reason I've had to house rule that MASC gets a free turn of success. 0, 3, 5, 7, etc. It already paid for its speed boost in BV -- It shouldn't be saddled with jamming if that isn't accounted for as a BV discount.

Well, but that's the thing:  it may not provide as much of a boost.  Sure, in this example, it increased the BV multipliers, but the defensive BV dropped because MASC weighed so much.  And it was only because of the particular Walk/Run combination on the base design.  Had it started off as an 8/12 'Mech, for example, MASC would not have improved the defensive BV calculation (8 x 2 = 16 MASC MP; moving 16 hexes = +4 TMM, same as moving 14 hexes, so defensive BV multiplier stays at x1.4).  Going the other way, if you had a light 'Mech that could already move 12/18, it's already getting a max TMM of +5 & defensive BV multiplier of x1.5; MASC only boosts it up to 24 MP, which is still that +5/x1.5 combination.  But barring Clan tech (or really stripping down an IS 'Mech), I don't know if it's even possible to get a 'Mech up to the 13/20 speed you'd need to get that final benefit from using MASC (26 MP = +6 TMM/x1.6 multiplier).  Fastest canon 'Mech so far to do that is the Celerity from Technical Readout 3145: Republic of the Sphere... but it's an ugly 15-ton Ultralight, needs an XXL engine to get to its base 16/24 speed in the first place, has the armor protection of the HSR-300-D (downgraded) Hussar, & it's a drone with only 2 tons of OmniMech pod space to boot (so trying to convert it to a manned version would require a smaller engine, even less armor, less pod space, or a combination of them).  What's weird is that you'd probably see more of a BV boost if, instead of dropping the armor & adding MASC, they'd simply replaced the Flamer with 2 Jump Jets.  No change to the defensive side, you have no heat issues to worry about, & your offensive multiplier still goes up from x2.16 to x2.30;  just doing a quick calculation, I think it would move the -1S up from 716 BV to 720 BV, & avoids any MASC issues whatsoever.

Again, you're trading off 1 kind of capability (short boosts) instead of using your tonnage for something else.  That's more on the design side than the BV side, & indirectly also involving the gameplay side.  Personally, I usually avoid adding MASC to my custom designs (because I worry about that activation issue), but at Origins this year I had some decent success with a MASC-equipped heavy allowing me to get better shots on targets that I couldn't have otherwise done.  Plus it's not really that bad of a failure option:  1-in-36 on the first turn, 1-in-12 on the 2nd turn, 5-in-12 on the 3rd turn, etc., but if you don't use it your chances drop back down; ideal usage would be use it 1 or 2 turns in a row, then not use it for a turn or 2, & you're only going to sweat a snake-eyes roll.

Same goes for jamming. A weapon that fires 2 rounds/turn and doesn't jam shouldn't be the same BV as one that does jam. That's broken. And that's how the current calculation is. (http://www.heavymetalpro.com/bv_calc.htm) Until that's fixed, I don't think any AC, Rotary or Ultra, should jam during a game. Not as long as they're being calculated as doing their full damage each turn. I agree that jamming is a fine thing and could be fun to include. But they'd have to say "this weapon gets a 30% discount on the final BV of the weapon if it jams during use," or something to that effect. Then at least you wouldn't be paying 100% for a weapon that turns into a useless hunk of metal after a few turns while your opponent's laser boat is firing unlimited.

But then what about weapons that explode when they're hit, even though (technically) they don't actually have anything that should explode (i.e. Gauss rifles), unless they're saying their capacitors are made of old Samsung batteries & washing machines?

Seriously, though, part of that is that they don't get the full damage of both shots.  For the calculation, it assumes that 2 shots are fired, but it takes the average chance of a shot hitting.  7-in-12 times only 1 shot hits, the other 5-in-12 times both hit, so it averages out to 1.4167 hits per double-tap.  If they were actually using the full damage, the Inner Sphere Ultra AC/10 would actually have a BV of 296, not 210 (with 37 BV per ton of ammo instead of 26), or basically double what a ballistic weapon doing 10 points of damage with Short/Medium/Long Range brackets of 6/12/18 hexes & no Minimum Range would have (148 for the gun, 19 for the ammo, in particular).

And I wouldn't worry too much about some of those laser boats.  Take the Nova Prime, for example:  a wondrous piece of Clan machinery.  Just as much armor as the identically-massed Hunchback, yet slightly faster than the Hunch, with 12 Clan ER Medium Lasers to ruin a Crunchy pilot's day since they can outrange it (not to mention the 84 points of max damage it can deal out)...theoretically, that it.  It only has 18 double heat sinks, though (36 dissipation), & at maximum (Alpha Strike & Jumping 5 hexes) it generates a massive 65 points of heat.  Bam...the Clanner just went up to 29 on the heat scale.  Next turn, he can only Jump (-5 MP vs. 5 Walking MP = no Walking or Running), he had 4 separate shutdown rolls to make (4+, 6+, 8+ & the dreaded 10+), & even if he managed to avoid all of that he's got a +4 Modifier to Fire next turn.  Basically, if he stands still he really needs to avoid firing more than 2 of his lasers (truly pathetic, especially compared to his previous Alpha Strike), & if he Jumps (which will give him a +7 modifier total) he's looking at only firing 1 laser...assuming he wants to get below 5 heat on the scale.  In the meantime, though, the Crunchy pilot should have little to no trouble getting close enough for his AC/20 to open a really big hole in the Nova (identical armor distribution between the 2 of them, so any hit other than to a Leg or Center Torso will automatically go internal; any backshots will completely destroy that torso section, removing the arm Lasers for that side & giving it 2 Engine Hits...or worse, taking out the Center Torso or Head completely).  If he keeps from Jumping at all, his heat is a little more manageable, but still gets the same results (max heat 62 - 36 dissipation = 27 on the heat scale from an Alpha strike, identical chances for shutdown)...but basically, the Clan pilot has to look at a large number of those ER Medium Lasers as "spares:  use only if others are destroyed or as an absolute last resort".  Basically, he can fire 6 lasers & Run/Jump without overheating at all, or fire 7 lasers & have to juggle down to 5 or 6 every couple of turns to cool off (& why, on the BV calculations, only the 1st 7 lasers got their full BV).  That's why the best "laser boats" are the ones that can keep firing their weapons without overheating, so that they're not using tonnage for "spare" weapons.

So does your theory account for smaller engines as well? i.e.: a 3/5 Mech at 70 tons has more tonnage free than a 4/6, so they should always be higher BV?

That's taken care of with the multipliers for movement:

• Defensively, the faster you can move, the higher your TMM; the higher your TMM, the harder it is for enemy pilots to hit you (& the easier it is to keep damaged/disabled sections away from enemy fire); the harder it is for your 'Mech to be hit, the longer its armor & structure will hold out before being destroyed
• Offensively, the faster you can move, the better the possibility that you can move into position to use your weapons (whether it's simply firing them at the enemy, maneuver to back-shoot them, or even just be able to target previously damaged/disabled sections on the enemy)

[TigerShark]

No, tonnage doesn't directly figure in.  It's more indirect, based on the overall tonnage you had available & how much you used for other equipment.  Same with heat:  using less-heat-intensive weapons means you don't have the design decision of either juggling weapons or having to "waste" tonnage & space on additional heat sinks, even if you're not trying to min/max the BV calculations.

I think we're talking two, different languages here. You're speaking abstractly. I'm talking specifics and math. If it doesn't have a number accounting for it, it doesn't matter what anecdotal evidence exists; it isn't part of the equation.

1 ton of free space = 25 BV

That's an equation. (No, that's not a true statement above. It's an example only.) Since free space has no BV assigned, it doesn't not factor into Battle Value.

1 ton of free space = 1 x IS Medium Laser
1 ton of free space = 2 x Clan ER Small Lasers

This, however, DOES have a BV. Why? Because the lasers have a BV. The IS Medium is 46 BV and each Clan ER Small is 31 BV (62 BV total). So just because you have 1 ton of free space does NOT mean that space has value. It only has value when something enters it.

So if I have an AC/10 (12 tons) and I remove that, I have 12 tons of free space. That space = 0 BV. If it gets filled with a larger engine (say, upgrading a 4/6 to a 5/8), the BV increase comes from the Offensive and Defensive BV increases. It's calculated elsewhere.

Again, you're trading off 1 kind of capability (short boosts) instead of using your tonnage for something else.  That's more on the design side than the BV side, & indirectly also involving the gameplay side.  Personally, I usually avoid adding MASC to my custom designs (because I worry about that activation issue), but at Origins this year I had some decent success with a MASC-equipped heavy allowing me to get better shots on targets that I couldn't have otherwise done.  Plus it's not really that bad of a failure option:  1-in-36 on the first turn, 1-in-12 on the 2nd turn, 5-in-12 on the 3rd turn, etc., but if you don't use it your chances drop back down; ideal usage would be use it 1 or 2 turns in a row, then not use it for a turn or 2, & you're only going to sweat a snake-eyes roll.

Very well. I'll put it in a different way. Let's say Catalyst brought out "Advanced MASC" and this new system does not jam at all. It simply doubles the Walking MP and subtracts the Running MP for the "MASC boost."

It does the exact, same thing as MASC. No changes other than it stops jamming. What is its new BV?

[Cryhavok101]

I think we're talking two, different languages here. You're speaking abstractly. I'm talking specifics and math. If it doesn't have a number accounting for it, it doesn't matter what anecdotal evidence exists; it isn't part of the equation.

I agree we may be speaking different languages lol. I can't speak for the other person, but I was only trying to explain why the BV doesn't need to account for the tonnage of an item, because what benefit or penalty you have based on it's weight ends up being adjusted for in the full equation, by putting on more (or less) gear to fill the space.

[theagent]

I think we're talking two, different languages here. You're speaking abstractly. I'm talking specifics and math. If it doesn't have a number accounting for it, it doesn't matter what anecdotal evidence exists; it isn't part of the equation.

1 ton of free space = 25 BV

That's an equation. (No, that's not a true statement above. It's an example only.) Since free space has no BV assigned, it doesn't not factor into Battle Value.

1 ton of free space = 1 x IS Medium Laser
1 ton of free space = 2 x Clan ER Small Lasers

This, however, DOES have a BV. Why? Because the lasers have a BV. The IS Medium is 46 BV and each Clan ER Small is 31 BV (62 BV total). So just because you have 1 ton of free space does NOT mean that space has value. It only has value when something enters it.

So if I have an AC/10 (12 tons) and I remove that, I have 12 tons of free space. That space = 0 BV. If it gets filled with a larger engine (say, upgrading a 4/6 to a 5/8), the BV increase comes from the Offensive and Defensive BV increases. It's calculated elsewhere.

Very well. I'll put it in a different way. Let's say Catalyst brought out "Advanced MASC" and this new system does not jam at all. It simply doubles the Walking MP and subtracts the Running MP for the "MASC boost."

It does the exact, same thing as MASC. No changes other than it stops jamming. What is its new BV?

A lot of times the cut-and-dried mathematics I love to deal with don't always work.  What looks like a great weapons loadout for a heavy or assault 'Mech, for example, would be ridiculous on a medium 'Mech & impossible to duplicate on a light 'Mech, once the actual math & equations start getting into play.  I do prefer looking more at the specifics...but that means we have to look at specific examples & comparisons, & I've found in BattleTech that sometimes the choice of comparisons gives you different results.

As for an "Advanced" MASC...if it used more tonnage/slots (which would also make it more expensive to build), I would be fine with it not having the chance to go belly-up in battle.  I'd probably be OK with double the normal tonnage (i.e. 10% of total tonnage for IS/8% of total tonnage for Clan, rounding all fractions up to the next whole ton) & slots (1 slot per ton).  I would probably be OK with increasing the adjustment on offensive BV, but only slightly (i.e. instead of adding +1 to the Running MP, I would say add +2, +3 tops).  That's the tradeoff:  extra tonnage (&, with extra slots, the increased chance of damaging the equipment) for the option of constantly going at twice my Walking speed instead of just 50% faster.  And indirectly, because I've spent the extra tonnage (range should be an extra 1-5 tons for IS, 1-4 tons for Clan), I have that much less tonnage available for other equipment. 

Take, for example, the HER-3S1 Hermes from earlier.  It already used 2 tons to add MASC; "Advanced" MASC would require 3 tons instead.  I can add it in by dropping 1 of the Medium Lasers, so now (as long as the MASC isn't damaged by critical hits) I can run around the map with 18 MP (maximum of +5 TMM)...although, since most maps have elevation changes & woods hexes scattered around, plus the need to turn corners, I'll probably end up only moving 12 actual hexes each turn (although that's still good enough for a +4 TMM), where without MASC I'd be lucky to move 8 actual hexes (+3 TMM).  But even with that Guardian ECM helping me, I'm not only a 'Mech that has to worry about Small Lasers, let alone Medium Lasers or heavier weapons, hitting most of my armor locations, I have only a single laser (a la Ostscout) to fire back with.  But that's my sacrifice:  trading weaponry & armor protection for more speed, gambling that it's better to try avoiding fire in the first place than trying to plan on withstanding it.

[theagent]

On a semi-related subject, though, has anyone wondered why we never had some of the autocannon types filled out?  Sure, it would be heavier & generate more heat, but I would think that a HVAC/20 would be really nasty.  And maybe a Light AC/10 or Light AC/20 might be a bit short on range, but so are the standard AC/20 & IS Medium Pulse Lasers (both of which, I think, would probably match the range of those Light ACs)...& would lend themselves nicely as a base to Rotary versions (probably difficult to put into a BattleMech, but the lack of heat would make them acceptable on Combat Vehicles, & they might work well as short-range "sweeper" weapons for DropShips or WarShips).

And on that subject...since the LB-X and Ultra ACs are just ACs that have been heavily modified (the former with lighter/bulkier alloys & cluster ammunition that gain a range boost, the latter modified to spit out 2 shells/bursts at a time), why wouldn't it be possible to build Light versions of them as well?

[TigerShark]

As for an "Advanced" MASC...if it used more tonnage/slots (which would also make it more expensive to build), I would be fine with it not having the chance to go belly-up in battle.  I'd probably be OK with double the normal tonnage (i.e. 10% of total tonnage for IS/8% of total tonnage for Clan, rounding all fractions up to the next whole ton) & slots (1 slot per ton).  I would probably be OK with increasing the adjustment on offensive BV, but only slightly (i.e. instead of adding +1 to the Running MP, I would say add +2, +3 tops).  That's the tradeoff:  extra tonnage (&, with extra slots, the increased chance of damaging the equipment) for the option of constantly going at twice my Walking speed instead of just 50% faster.  And indirectly, because I've spent the extra tonnage (range should be an extra 1-5 tons for IS, 1-4 tons for Clan), I have that much less tonnage available for other equipment. 

I get what you're trying to say. But you didn't answer my question: What BV is that piece of tech? I don't care about tonnage, or crits, or heat, or anything else.  None of those are in the BV calculations for equipment. And that's the entire subject I'm discussing: How BV is inaccurate for BattleTech's equipment.

So we'll just move on with this one. :) I'm guessing we won't see eye-to-eye. Just light years apart on how we balance things.

[Sabelkatten]

It doesn't do the same damage, since it's not an "all-or-nothing" scenario. i.e.: 5 AC/2s don't all hit every turn. While the LPL does do 100% of its damage with every hit. Also, Precision ammo only gives a -2 if your opponent generates a +2 or better. Clan LPL does this even when you stand still. And has no minimum range.

5x2 is as much as 10 the last time I checked...

I did point out that the LPL is better against slow targets, but then the value of the TN bonus is smaller against slow targets since they're (generally) easier to hit. Minimum range is more than made up for by having ~20% more range!

[theagent]

I get what you're trying to say. But you didn't answer my question: What BV is that piece of tech? I don't care about tonnage, or crits, or heat, or anything else.  None of those are in the BV calculations for equipment. And that's the entire subject I'm discussing: How BV is inaccurate for BattleTech's equipment.

So we'll just move on with this one. :) I'm guessing we won't see eye-to-eye. Just light years apart on how we balance things.

The problem is that they already had a system that assigned a "value" to every single component...the Combat Value [CV] system.  FASA introduced it in the Tactical Handbook back in 1994.  It was a precursor of Battle Value, in that it was supposed to allow you to compare the relative combat effectiveness of 2 'Mechs (irregardless of cost), & allow you to set up "balanced" encounters.

The problem was that it wasn't balanced.  Weapons & certain equipment like ECM or Active Probes had a fixed CV.  BattleMech components each had a calculated CV, either based on the # of points (Internal Structure, Armor) or the 'Mech tonnage.  There were some inherent problems with that, though:

• Components that had no tonnage, & had fixed sets of slots, had a CV assigned to them (Sensors, Life Support, Leg actuators, etc.).  But their CV ('Mech tonnage x 1) was equal to that of added items that used tonnage & slots (i.e. MASC).
• Endo Steel had twice the CV per point as standard structure, even though it's no tougher than standard structure
• For some of the weapons, there was little to no difference in CV between the IS & Clan versions, even when the Clan versions are superior in range, tonnage used, or other factors (i.e. Ultra ACs/SRMs/Streaks were identical, LB 10-X was identical, other LB-X literally only had a few more points, etc.)
• Certain items that were calculated based on 'Mech tonnage were done irregardless of the actual effect.  For example, Engine CV was based on 'Mech tonnage...so the Nissan 200 in an Annihilator (2/3) had the same CV as the Vlar 300 in an Atlas (3/5).  And even though XL engines are more delicate than standard engines, they have double the CV.  And a Targeting Computer?  A 100-ton 'Mech with a 3-ton TC received more CV than a 50-ton 'Mech with a 5-ton TC.  Or they might offer a fixed CV irregardless of the actual effect (i.e. both an LRM-5 & LRM-20 with Artemis IV received an extra 60 CV for the Artemis, even though the LRM-20 gets more of a benefit from it).

You can always go back to that system...but I'd say FASA pretty much determined that method was broken when they went with BV instead.

[TigerShark]

You can always go back to that system...but I'd say FASA pretty much determined that method was broken when they went with BV instead.

We don't disagree that CV was broken.

Example of what I'm looking for. As a note, this weapon DOES NOT EXIST. Its calculations for BV, however, are canon and are what's used currently. (http://www.heavymetalpro.com/bv_calc.htm)

Hypthetical Laser Weapon

Code: [Select]

BV: 37
Damage: 6Range: 2/4/6
To-Hit Modifier: +0
Now, if we take this weapon and apply a -1 to-hit modifier to it, it gains ~16% BV. No other changes are made.

Improved Hypthetical Laser Weapon

Code: [Select]

BV: 43 (+16.2%)
Damage: 6Range: 2/4/6
To-Hit
Modifier: -1
If we take our original, Hypothetical Laser, and make it a -2 Pulse weapon (making it the canon IS Medium Pulse), it gains ~29.7% over the unmodified, original version with no to-hit modifier. But it only gains ~13.5% over the version with the -1 bonus, making the -2 Pulse version a very good value.

IS Medium Pulse Laser

Code: [Select]

BV: 48 (+29.7%)
Damage: 6
Range: 2/4/6
To-Hit Modifier: -2

In these examples, we're giving hard BV modifiers to each quality. In general, if you extrapolate these numbers across different guns with different damage values (i.e.: the IS Large Pulse laser, but with +0 and -1 bonuses), you get a steady increase. It seems as if any laser with a -1 bonus to-hit increases its BV by approximately 16.5%. Any laser going from +0 to -2 sees an approximately 29.5% increase in BV.

The problem I have here is that weapon BV doesn't account for heat, crit space, or the ability to jam. Notice that on the website, there is NO FIELD for any of these factors. And I'd have to say that those are some pretty big factors.

What if the IS Medium Pulse laser incurred 6 heat? Would it still be worth 48 BV? How about 10 heat? Or, conversely, if it generated 0 heat every turn, would it not be more useful than 48 BV? You see, this value (Battle Value) is missing some parameters which DEFINITELY affect how useful a weapon is. And rather than throwing them on, willy nilly, I prefer to have these things accounted for in the calculation.

A really good example is the IS PPC vs. IS Prototype PPC. They are the EXACT, SAME weapon. Same tonnage, same damage, same crit space. Same BV. (176 BV) But the Prototype PPC generates 5 more heat than the IS PPC. Are you telling me that a weapon that generates 15 heat for 10 damage is the same usefulness as 10 heat for 10 damage? That should really stand out as a big "no." You can excuse it by saying "well, it's a prototype!" but this isn't balancing by tonnage. It's balancing by Battle Value, which is a number that has a complex calculation attached to it. BV is supposed to reflect how useful things are on the field. When they're given special qualities, it increases BV. When they receive drawbacks, it reduces it.

But that's not being accounted for currently. And, to get this back to the OP's post, that's a big reason Autocannons "suck." The weapons themselves are fine. The BV attached to them is flat-out incorrect.

[Sabelkatten]

Short response: You're wrong. BV accounts for heat, period. If using a prototype PPC will negatively effect a unit's performance it will have a lower BV.

And it's most definitely NOT the reason ACs sucks. ACs are treated pretty well by the BV system - if you use precision ammo you even get a free bonus!

Now, there's still a number of big problems with BV. But the only ones that hurts ACs are undervaluing the effect of ammo explosions, not accounting for heat efficiency in a good way (unintuitively the CBT rules means a weapon is in effect more heat efficient the MORE heat it produces), and - of course - for not accounting for jamming.

[RunandFindOut]

Short response: You're wrong. BV accounts for heat, period. If using a prototype PPC will negatively effect a unit's performance it will have a lower BV.

Not to dogpile on you but could you prove that by providing the math?  Because there are more than a few places in BV where the result does not appear to bear that out.

[Sabelkatten]

Can't find my document with the formulas, but every weapon that the heat sinks can't cover counts for half value. There are some extra rules for which weapons have to be halved first and last to try and avoid some of the exploits possible in BV1, and you count a number of heat sinks that's a bit higher than what you actually have (SSW says 6, I thought it was 4). The last is supposed to represent the advantage of "pushing the heat".

So if you put 3 prototype PPCs on a standard Awesome the last one should be halved.

Now, a big caveat on this: I don't remember all the "special cases" rules added to BV2 heat calculations and I can't look them up. There are probably a lot of silly faults in the system still. I know the theory is sound, but the actual execution leaves a lot to be desired.

[William J. Pennington]

Techmanual, page 303. Calculating BV for mechs,

STEP 2: CALCULATE OFFENSIVE BATTLE RATING

"If the total heat generated by all off ensive weapons fi re is
greater than the ’Mech Heat Effi ciency, then the player should
adjust the BV of some weapons to refl ect the ineffi ciency of
the ‘Mech design. Follow the steps listed below:
• Consult the appropriate Weapon and Equipment Battle
Value tables (see pp. 317–319) to fi nd the weapon that generates
heat when fi red and has the highest Battle Value.
• If more than one weapon has the same BV, choose the
one which generates the least heat. If multiple weapons
of the same type are mounted, just choose one. Always
choose rear-mounted weapons over forward-fi ring ones
of the same type (see Rear-Firing Weapons, below).
• Add the full BV of the weapon, and add its Heat Value to
the running heat total, beginning at zero.
• If this new heat is less than the ‘Mech Heat Efficiency,
repeat the above steps. Otherwise, add half the BV for
all remaining weapons to the Base Weapon Battle Rating,
then continue to the next step. The BV for the fi rst
weapon to equal or exceed the ‘Mech Heat Effi ciency is
counted at its full value, however.
• If this new running heat total is less than the ‘Mech
Heat Effi ciency, repeat the above steps, which value the
next weapon at full BV. Otherwise, add half the BV of all
remaining weapons to the Base Battle Rating, then continue
to the next step. (This method values any weapon
whose heat increases the total running heat from below
the ‘Mech Heat Effi ciency, to above it, at full BV.)"

[TigerShark]

Can't find my document with the formulas, but every weapon that the heat sinks can't cover counts for half value. There are some extra rules for which weapons have to be halved first and last to try and avoid some of the exploits possible in BV1, and you count a number of heat sinks that's a bit higher than what you actually have (SSW says 6, I thought it was 4). The last is supposed to represent the advantage of "pushing the heat".

So if you put 3 prototype PPCs on a standard Awesome the last one should be halved.

Now, a big caveat on this: I don't remember all the "special cases" rules added to BV2 heat calculations and I can't look them up. There are probably a lot of silly faults in the system still. I know the theory is sound, but the actual execution leaves a lot to be desired.

You mentioned an Awesome. I presume you mean the AWS-8Q.

Stock BV: 1605
BV with 3x Prototype PPC: 1600

A savings of 5 BV. Total. For the complete inability to fire more than 2 PPCs in a turn without going +17 over. Here's the BV calc to back it up. And why? Because the heat calculation is busted. For some reason, they've (developers) miscalculated at +6 for the heat, then added in the maximum heat for running/jumping. As a refresher, this means that anything firing over [ weapon heat + 6 - movement heat - heat sinks] gets discounted at 50%. It should be +0. [weapon heat - movement heat - heat sinks ]. A lot more weapons should get getting the 50% discount; especially on SHS designs.

But even further, even IF that 50% discount were applied to the extra Prototype PPC, it would only discount the entire design by 88 BV ( 176 * 0.5 = 88 ). 33% of your firepower gone and only a 5.5% total BV discount. That should immediately stand out as "broken."

Code: [Select]

Defensive BV Calculation Breakdown
________________________________________________________________________________
Total Armor Factor (240) * Armor Type Modifier (1.0) * 2.5                600.00
Total Structure Points (122) * Structure Type Modifier (1.0)
    * Engine Type Modifier (1.0) * 1.5                                    183.00
Mech Tonnage (80) * Gyro Type Modifer (0.5)                                40.00
Total Defensive BV of all Equipment                                         0.00
Excessive Ammunition Penalty                                                0.00
Explosive Ammunition Penalty                                                0.00
Explosive Item Penalty                                                      0.00
Subtotal                                                                  823.00
Defensive Speed Factor Breakdown:
    Maximum Ground Movement Modifier: 1.20
    Maximum Jump Movement Modifier:   0.00
    Defensive Speed Factor Bonus from Equipment: 0.00
    Minimum Defensive Speed Factor:   0.00
    (Max of Run or Jump) + DSF Bonus = 1.20
Total DBV (Subtotal * Defensive Speed Factor (1.20))                      987.60


Offensive BV Calculation Breakdown
________________________________________________________________________________
Heat Efficiency (6 + 28 - 2) = 32
Adjusted Weapon BV Total WBV                                              532.50
    -> Prototype PPC                                                      176.00
    -> Prototype PPC                                                      176.00
    -> Prototype PPC                                                      176.00
    -> Small Laser                                                          4.50
Non-Heat Equipment Total NHBV                                               0.00
Excessive Ammunition Penalty                                                0.00
Mech Tonnage Bonus                                                         80.00
Subtotal (WBV + NHBV - Excessive Ammo + Tonnage Bonus)                    612.50
Offensive Speed Factor Breakdown:
    Adjusted Running MP (5) + ( Adjusted Jumping MP (0) / 2 ) - 5 = 0.00
    0.00 / 10 + 1 = 1.000
    1.00 ^ 1.2 = 1.0 (rounded off to two digits)
Total OBV (Subtotal * Offensive Speed Factor (1.0))                       612.50


Total Battle Value (DBV + OBV, round off)                                  1,600

[Hptm. Streiger]

Example of what I'm looking for. As a note, this weapon DOES NOT EXIST. Its calculations for BV, however, are canon and are what's used currently. (http://www.heavymetalpro.com/bv_calc.htm)
..
..
The problem I have here is that weapon BV doesn't account for heat, crit space, or the ability to jam. Notice that on the website, there is NO FIELD for any of these factors. And I'd have to say that those are some pretty big factors.

What if the IS Medium Pulse laser incurred 6 heat? Would it still be worth 48 BV? How about 10 heat? Or, conversely, if it generated 0 heat every turn, would it not be more useful than 48 BV? You see, this value (Battle Value) is missing some parameters which DEFINITELY affect how useful a weapon is. And rather than throwing them on, willy nilly, I prefer to have these things accounted for in the calculation.

But that's not being accounted for currently. And, to get this back to the OP's post, that's a big reason Autocannons "suck." The weapons themselves are fine. The BV attached to them is flat-out incorrect.

The BV is an abstract value it does reflect some "Battle" impacts - range and average to hit probability.
The base to hit number is not modified (you hardly need only a +4 in average combat - and this differs from target to target)
For example the -2 bonus of the LPL might be the only mean that you are able to hit some targets at all.

Also a -3 modifier would not change the values for short range because they are already at 2+ = 100% with -2 to hit modification.

for weight and heat you can use a "benchmark of your own" (consider, heat ammunition and weight (maybe crits)) and compare it with the BV

as mentioned before at intro level there was no BV necessary because the tonnage was a good benchmark - or at least would have been if you would ignore the free heat sinks.

However as mentioned heat and weight are not directly considered in the weapon calculation because this are mech interna. The weight of a weapon does not have effect on its ability in battle (maybe with some tac-ops optional rules) - same for heat and if you can't fire 3 weapons without overheating doesn't mean you can't fire them at all.
So a Mech with 2 PPCs should always have less BV when compared with a Mech with 3 PPCs but only heat sinks to use 2.

However - I'm working at a thing I called "thread value" for each weapon system. The goal is a global value that reflect the number of shots fired with this weapon to destroy a single target. Had some "generic" targets before and I'm improving the system now to reflect different Mechs with different criticals - I will add the target mobility into the construct as well.

[Cryhavok101]

Is there actually a cannon rule for how BV is calculated for s single piece of equipment? As far as I know that has been kept from us. If I am wrong, would someone point me to the book and page number?

[Hptm. Streiger]

the rules are hidden, but you can calculate them backwards (like we did for the Sub Capital Weapons - and the Abstract aerospace brackets)
first the BV weapon calculator give some insight

to hit probability * damage (average number for cluster) - sum together

for example ((33+26+15)*3)/36 for the Small Laser * 1.5 for energy weapon = 9
for the small pulse laser it would be ((33+26+15)*3)/36 because of the -2 to hit modificator

http://www.heavymetalpro.com/bv_calc.htm
for switchable ammo - LBX the calculation is for the Slug - 148 to 108 for cluster


there are lots of loop holes - so you should use common knowledge to prevent "custom" weapons
TigerSharks example of the Med Pulse
what about a Snub Med Pulse

Code: [Select]

BV: 42
Damage: 6/3/1
Range: 4/5/6
To-Hit
Modifier: -4
(not to mention that different optional rules might cause a extreme different performance.

What you can do to "solve some issues"  - you could change the to hit modifier to +3 for standard weapons (you still have +4 for MRMs)
you also could reduce the damage at long ranges when you use ammunition depended weapons

Code: [Select]

MPLAS BV: 31
Damage: 6/6/6
Range: 2/4/6
To-Hit
Modifier: (+1)-2

Code: [Select]

MLAS BV: 21
Damage: 5/5/5
Range: 3/6/9
To-Hit
Modifier: (+3)0

Code: [Select]

ERMLAS BV: 28
Damage: 5/5/5
Range: 4/8/12
To-Hit
Modifier: (+3)0
this would make the "Snub Pulse of above more expensive compared to the MPLAS (would be 40)with this change

[Sabelkatten]

You mentioned an Awesome. I presume you mean the AWS-8Q.

Stock BV: 1605
BV with 3x Prototype PPC: 1600

A savings of 5 BV. Total. For the complete inability to fire more than 2 PPCs in a turn without going +17 over. Here's the BV calc to back it up. And why? Because the heat calculation is busted. For some reason, they've (developers) miscalculated at +6 for the heat, then added in the maximum heat for running/jumping. As a refresher, this means that anything firing over [ weapon heat + 6 - movement heat - heat sinks] gets discounted at 50%. It should be +0. [weapon heat - movement heat - heat sinks ]. A lot more weapons should get getting the 50% discount; especially on SHS designs.

But even further, even IF that 50% discount were applied to the extra Prototype PPC, it would only discount the entire design by 88 BV ( 176 * 0.5 = 88 ). 33% of your firepower gone and only a 5.5% total BV discount. That should immediately stand out as "broken."

Code: [Select]

Defensive BV Calculation Breakdown
________________________________________________________________________________
Total Armor Factor (240) * Armor Type Modifier (1.0) * 2.5                600.00
Total Structure Points (122) * Structure Type Modifier (1.0)
    * Engine Type Modifier (1.0) * 1.5                                    183.00
Mech Tonnage (80) * Gyro Type Modifer (0.5)                                40.00
Total Defensive BV of all Equipment                                         0.00
Excessive Ammunition Penalty                                                0.00
Explosive Ammunition Penalty                                                0.00
Explosive Item Penalty                                                      0.00
Subtotal                                                                  823.00
Defensive Speed Factor Breakdown:
    Maximum Ground Movement Modifier: 1.20
    Maximum Jump Movement Modifier:   0.00
    Defensive Speed Factor Bonus from Equipment: 0.00
    Minimum Defensive Speed Factor:   0.00
    (Max of Run or Jump) + DSF Bonus = 1.20
Total DBV (Subtotal * Defensive Speed Factor (1.20))                      987.60


Offensive BV Calculation Breakdown
________________________________________________________________________________
Heat Efficiency (6 + 28 - 2) = 32
Adjusted Weapon BV Total WBV                                              532.50
    -> Prototype PPC                                                      176.00
    -> Prototype PPC                                                      176.00
    -> Prototype PPC                                                      176.00
    -> Small Laser                                                          4.50
Non-Heat Equipment Total NHBV                                               0.00
Excessive Ammunition Penalty                                                0.00
Mech Tonnage Bonus                                                         80.00
Subtotal (WBV + NHBV - Excessive Ammo + Tonnage Bonus)                    612.50
Offensive Speed Factor Breakdown:
    Adjusted Running MP (5) + ( Adjusted Jumping MP (0) / 2 ) - 5 = 0.00
    0.00 / 10 + 1 = 1.000
    1.00 ^ 1.2 = 1.0 (rounded off to two digits)
Total OBV (Subtotal * Offensive Speed Factor (1.0))                       612.50


Total Battle Value (DBV + OBV, round off)                                  1,600

..."should".

Yeah, I didn't remember all the rules. Most of my memories is from back when BV2 was new and people were discussing how it ought to be, and I misremembered. I thought it was the first weapon that ran over that got halved, not the second.

Anyway, my point stands: BV does account for weapon heat. It doesn't do it well, but it's still in there.

Now if you can come up with a better way of doing it I'll cheer you on, but I'll have to warn you that a lot of people have tried - and failed. :(

[Cryhavok101]

the rules are hidden, but you can calculate them backwards (like we did for the Sub Capital Weapons - and the Abstract aerospace brackets)
first the BV weapon calculator give some insight

to hit probability * damage (average number for cluster) - sum together

for example ((33+26+15)*3)/36 for the Small Laser * 1.5 for energy weapon = 9
for the small pulse laser it would be ((33+26+15)*3)/36 because of the -2 to hit modificator

http://www.heavymetalpro.com/bv_calc.htm
for switchable ammo - LBX the calculation is for the Slug - 148 to 108 for cluster

Does that calculator produce BV numbers that match all of Total War's weapons? Or are some of them off a bit?

[TigerShark]

Anyway, my point stands: BV does account for weapon heat. It doesn't do it well, but it's still in there.

No, it doesn't stand, IMO. As shown, it accounts for weapon OVER-heating. Whether a weapon does 15 heat or 10 heat or 1 heat, the BV of the weapon itself remains the same.

Well, it wouldn't be incredibly complex to do so. Discounting a weapon's final BV by "penalties" would go a long way in accounting for heat. For example (just hypothetical), at the end of the calculation, you count each point of heat generated and this becomes a percentage subtracted from the final BV (rounding down). Since every weapon in the game that generates heat would get a discount, this would end up balancing out in the end.


Or, conversely, if we simply repair the erroneous addition of 6 heat to the threshold, that would also qualify the third PPC for a discount. Removes (some of) the need to account for heat in weapon BV:

AWQ-8Q (current): 1605
AWS-8Q (standard PPC, remove 6 threshold): 1605
AWS-8Q (prototype PPC, remove 6 threshold): 1512 (5.8% drop)

It would also help eliminate some of the nonsensical problems involved with converting units over to Double Heat Sinks. For example, a PXH-1 with single heat sinks and one with double heat sinks is the same BV. This is obviously in error and it's directly caused by the +6 in the heat calculation.

PXH-1 (double heat sinks): 1041
PXH-1 (single heat sinks - current): 1041
PXH-1 (single heat sinks - proposed): 997 (4.2% drop)

[TigerShark]

Does that calculator produce BV numbers that match all of Total War's weapons? Or are some of them off a bit?

It matches. Try it out. :)

[Cryhavok101]

Awesome.... in that case I'm going to use it to fill in the BV for all those random scattered infantry weapons that don't have BV, but do have total war stats lol. (sorry, off subject, I know).

[Sabelkatten]

No, it doesn't stand, IMO. As shown, it accounts for weapon OVER-heating. Whether a weapon does 15 heat or 10 heat or 1 heat, the BV of the weapon itself remains the same.

Well, it wouldn't be incredibly complex to do so. Discounting a weapon's final BV by "penalties" would go a long way in accounting for heat. For example (just hypothetical), at the end of the calculation, you count each point of heat generated and this becomes a percentage subtracted from the final BV (rounding down). Since every weapon in the game that generates heat would get a discount, this would end up balancing out in the end.

The weapon BV remains the same because the weapon's heat output doesn't effect the weapons performance!

A standard or prototype PPC has exactly the same effect when used, thus the same BV.

However the mounting unit is effected by the increased heat output, so when you look at the entire unit you can calculate a penalty to its final BV based on its heat efficiency.

The most obvious demonstration on the ridiculous effect on changing weapons' BV depending on their heat is that you now need two BVs for every weapon - one for vehicles and one for mechs!

Or, conversely, if we simply repair the erroneous addition of 6 heat to the threshold, that would also qualify the third PPC for a discount. Removes (some of) the need to account for heat in weapon BV:

AWQ-8Q (current): 1605
AWS-8Q (standard PPC, remove 6 threshold): 1605
AWS-8Q (prototype PPC, remove 6 threshold): 1512 (5.8% drop)

It would also help eliminate some of the nonsensical problems involved with converting units over to Double Heat Sinks. For example, a PXH-1 with single heat sinks and one with double heat sinks is the same BV. This is obviously in error and it's directly caused by the +6 in the heat calculation.

PXH-1 (double heat sinks): 1041
PXH-1 (single heat sinks - current): 1041
PXH-1 (single heat sinks - proposed): 997 (4.2% drop)

Tweaks like that could make things better, but you'll still have problems with bracket fire units vs. alpha babies, "every-other-turn" units (IIRC that's the reason for the 6 heat), heavy laser abuse (currently, adding powerful high-heat weapons to a mech can actually lower its BV!) and probably some more cases that I can't think of right now.

The only way that I know of that might actually give a good BV account for both heat, range, and damage is to set up optimal firing solutions for every range from 1 to maximum and calculate a value from that - needless to say, that gets ridiculously complicated real fast!

[theagent]

the rules are hidden, but you can calculate them backwards (like we did for the Sub Capital Weapons - and the Abstract aerospace brackets)
first the BV weapon calculator give some insight

to hit probability * damage (average number for cluster) - sum together

for example ((33+26+15)*3)/36 for the Small Laser * 1.5 for energy weapon = 9
for the small pulse laser it would be ((33+26+15)*3)/36 because of the -2 to hit modificator

http://www.heavymetalpro.com/bv_calc.htm
for switchable ammo - LBX the calculation is for the Slug - 148 to 108 for cluster


there are lots of loop holes - so you should use common knowledge to prevent "custom" weapons
TigerSharks example of the Med Pulse
what about a Snub Med Pulse

Code: [Select]

BV: 42
Damage: 6/3/1
Range: 4/5/6
To-Hit
Modifier: -4
(not to mention that different optional rules might cause a extreme different performance.

What you can do to "solve some issues"  - you could change the to hit modifier to +3 for standard weapons (you still have +4 for MRMs)
you also could reduce the damage at long ranges when you use ammunition depended weapons

Code: [Select]

MPLAS BV: 31
Damage: 6/6/6
Range: 2/4/6
To-Hit
Modifier: (+1)-2

Code: [Select]

MLAS BV: 21
Damage: 5/5/5
Range: 3/6/9
To-Hit
Modifier: (+3)0

Code: [Select]

ERMLAS BV: 28
Damage: 5/5/5
Range: 4/8/12
To-Hit
Modifier: (+3)0
this would make the "Snub Pulse of above more expensive compared to the MPLAS (would be 40)with this change

One small problem:  if you're going to have a 'Mech have 3 Prototype PPCs, then you have to consider when those were in use.  In other words, if you're using 'primitive' weapons, that means you're putting them in a Primitive 'Mech.  That means a Primitive Cockpit, Primitive Fusion Engine, & Primitive Armor,  since the Prototype PPC ended production in 2460, but even the Terran Hegemony didn't switch over to non-primitive equipment until 2470.

That means:

• Drop down to a Primitive 195 engine to save 3.5 tons on the engine & 1 ton on the Gyro. Defensive BV multiplier drops down to X1.1, Offensive BV multiplier drops down to x0.77
• Primitive Cockpit uses 2 of those 'saved' tons.
• The other 2.5 tons is used for more armor, but because it's Primitive you lose 13 points.
• Because of those changes, Defensive BV drops to 759.55 & Offensive BV drops to 471.625.  Final BV is now 1231...significantly lower than the stock Awesome.
  

A better example would be the MSK-5S Mackie, since the 'PPC' it has would have originally been the Prototype version.  Unfortunately, it's not as useful because BV calculations show it getting full weapon BV with the standard PPC, but it drops half the AC/5's BV with the Prototype PPC.  But you could always change it out for 3 Prototype PPCs.  You get the same BV whether they're prototypes or regulars, but you're also massively overheating both in combat & in BV calculations.

[theagent]

For some less theoretical comparisons:

• CN9-A Centurion has AC/10 (2 tons ammo), LRM10 (2 tons ammo), & 2 MLs (1 rear-facing), with 10 heat sinks & 8.5 tons of armor.  BV formula lets it get full value for all weapons (half for the rear ML).
• CN9-AL model swaps out the AC/10 for a LL & a SL, plus 2.5 tons more armor & 6 more heat sinks.  BV formula still allows for full values.
• BV increased from 967 to 1091...but only because of the extra Defensive BV.  Offensive BV actually dropped (from 463.68 to 440.16).

[Alsadius]

Unfortunately, many factors just aren't accounted for in BattleValue.

• Heat: 0 damage and 10 heat? Same BV as 10 damage and 15 heat.
• Jamming: 10 damage per shot, 2 shots max (Ultra AC/10). Same BV whether it jams or not.
• Tonnage: Whether it's 100 tons or 10 tons, it doesn't matter. Tonnage doesn't count.
• MASC Failure: A MASC system that propels a unit to 8 MP (4/6[8]) gives the unit the same BV as a natural 8 (5/8).
• Ammunition: A weapon with 0 shots of ammo is the same BV as one with 100 shots.

A few of those are false. Heat does get included in BV - any weapons that take a mech above +6 heat with movement are only counted at half their base BV. If you're a mech with 10 DHS and have no other weapons, a Clan ERPPC and a Gauss Rifle will have basically the same BV(assuming 2t of ammo and if you fuzz over their slightly different range brackets), but if you're trying to mount one on a mech that already has half a dozen MLs, the numbers will be very different. (Technically, the highest BV weapons are counted first, so the hypothetical Gauss and ERPPC would have the same BV, but the MLs would be different - probably four of them would be counted at half, saving you 92 base BV)

Tonnage is directly included in the formula - one point of BV per ton is included in the offensive BV formula.

Ammo is accounted for, though it's done poorly IMO. A non-ammo-using weapon has 25% more BV than an identical ammo-using weapon has when it's dry, and ammo adds 1/8 of the base BV per ton. So a weapon with 2t of ammo has the same BV as an otherwise-identical energy weapon does. This is pretty reasonable for most weapons, where a ton is perhaps 8-20 shots, and thus two tons will be enough for most engagements. But for weapons like a HAG40, it falls apart, and with machine guns it's kind of silly. IMO, it should be done by shots per gun, not by tons, but that's probably annoying.

MASC is an odd one, because the published TechManual actually had it penalized on the offensive BV side by the text of the rules, but because the tables didn't penalize it, they errata'd it to match up with the table. I agree, that's an issue.

[Cryhavok101]

Tonnage is directly included in the formula - one point of BV per ton is included in the offensive BV formula.

Only Mech's and vehicles count the unit's weight in the BV calculations. For vehicles it is weight/2. Nothing else does. For mechs I assumed it was to represent the battlevalue of kicking and punching, and vehicles their ramming, but Protomechs don't add anything for the possibility of a frenzy, battle armor don't account for swarm, and aerospace stuff doesn't account for ramming, so your guess is as good as mine on that account.

[TigerShark]

A few of those are false. Heat does get included in BV - any weapons that take a mech above +6 heat with movement are only counted at half their base BV.
...Tonnage is directly included in the formula - one point of BV per ton is included in the offensive BV formula.

As I showed above, heat is not tracked. And because 50% is only taken off of the lowest-BV weapons, you'll never see a reasonable discount. So if your 'Mech has, say, three Clan ER PPCs and that's it, you won't be getting a discount on the big guns that you can't use since there's an odd exception for the weapon that actually crosses the threshold. It SHOULD be that any weapon going over the threshold is 50% BV, not the SECOND weapon to do so.

Example: I have a Mech with 16 DHS (32 heat dispersal). I have (3) Clan ER PPCs and it can only walk. 32 + 6 - 2 (walking) = 36 heat threshold. That means that all three ER PPCs will be counted, despite my being +15 heat if I choose to fire the third one and run in the same turn.

Example 2: I have a Mech with 16 DHS (32 heat dispersal). It has (2) Clan ER PPCs and (6) Clan ER Mediums. 36 heat threshold. That means (4) of the Clan ER Mediums will be at 50% BV (54 BV drop for each) meaning this 'Mech gets a 216 BV discount for heat.

That's a rather silly rule and it creates a big disparity in usefulness vs. BV. If we apply the fixes I proposed (remove the +6 and discount any weapon going over the threshold), both 'Mechs would receive (roughly) the same discount (206 for the 3rd Clan ER PPC).

Another good example would be the Orion ON1-K. This 'Mech is PLAGUED with overheating problems, especially if it takes an engine hit or is hit with inferno missiles of any kind. By moving the heat threshold from 14 down to 8, you discount both Medium lasers, giving it a ~52 BV discount ((23 + 23) * 1.12 speed factor). It's still a bad design, but at least it's not paying full price for weapons it couldn't possibly fire in the same turn as the LRM-15 and AC/10. This would bring the heat discounting in parity with bracket firing, which is where it should be.

[Alsadius]

The heat formula is a bit oversimplified, of course. Ideally, the weapon that crosses the threshold will be pro-rated accordingly - there's a big difference between the third PPC on an AWS-8Q that's mostly-sunk, and a hypothetical AWS-8Q2 that is otherwise identical except that it drops 5 HS to add a C3 master(or whatever). The current formula treats both identically, but then so does your proposed amendment, and I think that's a mistake.

That said, I disagree about your claim that the discounts are unreasonably low. Let's look at a fairly reasonable multi-range mech, the Stalker 3F. 2 LRM-10, 2 LL, 4 ML, 2 SRM-6, on 20 HS. At long range you fire the LRMs and LLs for +4 heat, and at short range you fire the MLs and SRMs for +0 heat, but in most cases it'll be one or the other. The LRMs are 90 BV, the LLs are 123, the MLs are 46, and the SRMs are 59, so it'll be added as LL > LRM > SRM > ML. The LLs and one LRM will add no heat, and the second LRM won't take it above the +6 even with movement heat, so those will be added at full price on BV. The MLs and SRMs will be half price, so you'll save 92 on the MLs and 59 on the SRMs, plus another 7 on SRM ammo, for a total of 158 BV - that is not a small discount. Maybe the second LRM should be half-price as well, for another -45, but that's arguable either way.

Also, I never thought the ON1-K was particularly bad for heat. Like the Stalker, it's a multi-range mech - LRM and AC at long range, SRM and MLs(or 1 ML and the AC) at short range. It has good alpha potential, but it can be used quite sustainably. That said, you're right about the +6 being particularly brutal in its case - trying to use it the way that BV says it could be used makes it a flamethrower very quickly. I understand the concept behind having a bit of excess to allow mechs to start playing in the 1-4 heat range, but +6 is too much for that. Probably a victim of simplification, but it's unfortunate sometimes.

[TigerShark]

The heat formula is a bit oversimplified, of course. Ideally, the weapon that crosses the threshold will be pro-rated accordingly - there's a big difference between the third PPC on an AWS-8Q that's mostly-sunk, and a hypothetical AWS-8Q2 that is otherwise identical except that it drops 5 HS to add a C3 master(or whatever). The current formula treats both identically, but then so does your proposed amendment, and I think that's a mistake.

That said, I disagree about your claim that the discounts are unreasonably low. Let's look at a fairly reasonable multi-range mech, the Stalker 3F. 2 LRM-10, 2 LL, 4 ML, 2 SRM-6, on 20 HS. At long range you fire the LRMs and LLs for +4 heat, and at short range you fire the MLs and SRMs for +0 heat, but in most cases it'll be one or the other. The LRMs are 90 BV, the LLs are 123, the MLs are 46, and the SRMs are 59, so it'll be added as LL > LRM > SRM > ML. The LLs and one LRM will add no heat, and the second LRM won't take it above the +6 even with movement heat, so those will be added at full price on BV. The MLs and SRMs will be half price, so you'll save 92 on the MLs and 59 on the SRMs, plus another 7 on SRM ammo, for a total of 158 BV - that is not a small discount. Maybe the second LRM should be half-price as well, for another -45, but that's arguable either way.

Also, I never thought the ON1-K was particularly bad for heat. Like the Stalker, it's a multi-range mech - LRM and AC at long range, SRM and MLs(or 1 ML and the AC) at short range. It has good alpha potential, but it can be used quite sustainably. That said, you're right about the +6 being particularly brutal in its case - trying to use it the way that BV says it could be used makes it a flamethrower very quickly. I understand the concept behind having a bit of excess to allow mechs to start playing in the 1-4 heat range, but +6 is too much for that. Probably a victim of simplification, but it's unfortunate sometimes.

You're accounting for single rounds. I'm thinking of an entire battle. The Stalker STK-3F can fire (2) Large Lasers, (1) LRM-10 and run in the same turn. ( 8 + 8 + 4 + 2 = 22 (+2 heat), 21 damage average, 26 max ) So what happens next turn? What's your bracketing then? If you go over +4, you lose the ability to generate a movement modifier without going "negative" and running for a +1 THM -- Something a better-sinked unit doesn't need to deal with.

( 2 (heat) + 8 (LL) + 8 (LL) + 4 (LRM) + 2 (running) = 24 (+4 heat) ). That's your turn 2, presumably. 21 damage average, 26 max, yes? But that's not what the BV formula states. According to the formula, both large lasers and both LRMs are available each turn. The discounting doesn't occur until the SRM-6s come into play during the calculation. So even though the 2nd LRM or 2nd Large Laser are only going to be fired every-other-turn (aka 50% of the time.. looks familiar, right?), they're being dinged at full BV. If you keep this same curve, you can only fire the LL and stay under the +5 threshold.

With the suggestions I made, the STK-3F discounts BOTH LRM-10s at 50%, giving the 'Mech at 90 BV discount from current. (5.77% drop). Basically, anything that exceeds +0 heat is discounted, since you'll eventually need to pause and have a turn where you're not firing. I do agree, however, that some kind of prorating would be better. +1 over isn't the same as +4 or +15.

As for the ON1-K, the problem isn't within the bracketing. It's that it's not sturdy when it comes to incurring additional heat. If infernos are on the table, if it takes an engine critical, if you're using atmospheric rules from TacOps, or if you are moving through/standing in a fire, your ability to use your weapons is either diminished or removed entirely. A single SRM-6 salvo loaded with inferno can cause your 'Mech to blow up in one turn (unless you're using the TacOps heat scale). At best you'll be hobbled with an average of +8 heat.

[Cryhavok101]

I think the thing the canon BV heat calculations are try to account for is the fact that Mechs (and aerospace fighters) CAN actually overheat. They can operate at above net 0 heat, where every other unit in the game has to be built to maintain heat neutrality. The BV calculation for mechs and fighters tries to reflect that... or at least it seems that way to me.

[theagent]

The main reason that the the BV for individual weapons doesn't account for heat, tonnage, or slots is because those are accounted for in other areas.  Basically, a weapon's BV assumes an ideal circumstance (base TN of 4 to hit at Short Range, which assumes a Wet Behind the Ears/Gunnery 7 operator, using remote/drone controls at +1 modifier, to fire on a gunnery range at an immobile target with the -4 modified; 7+1-4 = 4), & assumes a) any weapons that need ammo have it, & b) that all heat is dissipated by enough heat sinks for testing purposes.   It literally just measures how much damage is done over the given range.

Tonnage & slots are accounted for in the construction phase.  Available tonnage & slots for weapons is limited by engine size, allocated armor, use of advanced materials like Endo Steel or double heat sinks, etc.  You can't physically put an AC20 in a 20-ton 'Mech, & putting an AC10 in would give you a lighter & easier to kill Urbie...but only arming an 80-ton 'Mech wit an AC20 means a lot of tonnage gets wasted.

Heat comes into play with the BV calculation.  If you skimp on the heat sinks to pack as much weaponry as possible into a 'Mech, you can still have a high BV, but in gameplay you'll find a lot of the firepower wasted.  Conversely, unless you're just using the default 10 heat sinks, leaving excess heat dissipation can be just as wasteful.

[Cryhavok101]

You can't physically put an AC20 in a 20-ton 'Mech

I present to you the H4-H4 Yesican:

Code: [Select]

H4-H4 Yesican
Clan experimental
20 tons 
BV: 526
Cost: 1,897,740 C-bills

Movement: 3/5
Engine: 60 XL
Heat Sinks: 10 [20]
Cockpit: Small Cockpit
Gyro: Standard Gyro

Internal: 33 (Endo-Steel)
Armor: 9/69 (Ferro-Fibrous)
                     Internal    Armor
--------------------------------------
Center Torso                6        2
Center Torso (rear)                  0
Right Torso                 5        1
Right Torso (rear)                   0
Left Torso                  5        1
Left Torso (rear)                    0
Right Arm                   3        0
Left Arm                    3        0
Right Leg                   4        0
Left Leg                    4        0

Weapon                         Loc  Heat
----------------------------------------
Ultra AC/20                    RT/CT     7
ER Small Laser                  HD     2

Ammo                           Loc Shots
----------------------------------------
Ultra AC/20 Ammo                RT     5
Ultra AC/20 Ammo                RT     5



[Thunderbolt]

...Where I think we might be missing out, though, is the use of specialized ammo for the Rifle (Cannon) from Tactical Operations.  Per the note at the bottom of page 338, they only use "standard" ammo.  However, these are the cannons that truly correspond to our real-world weapons (like the old M68 105mm or Rheinmetall 120mm tank cannons)...

Comparing BT "cannons" with "autocannons" shows that the ACs are ~2X the mass of the corresponding Cs.

Similarly, rummaging around on Wikipedia, it appears multi-barrel Rotary ACs are ~2x the mass of single-barrel guns.  Also it appears that gun mass scales roughly as the square of the bore diameter, and that 120-130mm cannons mass 3.5-4.0tons.

Throwing an idea out there,

AC/2 --> 100mm RAC
AC/5 --> 125mm RAC
AC/10 -> 150mm RAC
AC/20 -> 175mm RAC

Think that would agree with some of the novel "fluff" and be physically plausible.  Inexpertly, the BT rules appear plausible, because smaller diameter guns can have proportionately longer barrels (55-66x the bore size) than larger guns (x33-44 say)... such that effective accuracy & range could wind up being inversely proportional to gun class.  Furthermore, BT already has "long barreled" (HV-) and "snub nosed" (light-) ACs that account for varying barrel length at constant bore size.

Keep all the tonnages & crits the same, just up ACs to something like TacOps rapid fire / RAC rapid fire rules.  UACs & RACs extra tons would represent "recoil compensation" affording additional bonus to-hit modifiers.

Somewhere the "fluff" states that one AC attack represents a burst of 3-5 rounds.  And 125mm (=AC/5) rounds weigh around 10kg apiece or 100 per ton. 

So I offer that one AC "shot" is a burst of 5 rounds or "once around" (1 round per barrel), and that all AC "shots per ton" be multiplied x5 to calculate actual individual "rounds per ton".

AC/2 --> 100mm RAC (5 barrels) w/ 225 rounds per ton (250?)
AC/5 --> 125mm RAC (5 barrels) w/ 100 rounds per ton
AC/10 -> 150mm RAC (5 barrels) w/ 50 rounds per ton
AC/20 -> 175mm RAC (5 barrels) w/ 25 rounds per ton

Multi-barrel RACs can have very high RoF such that "ACs" (interpreted as advanced 5-barrel RACs) could churn through >100 rounds per BT turn (albeit with increasingly enormous "recoil" to-hit penalty modifiers).

[Aposiopesis]

I've done this before (I actually have a full rebalance of all the weapons of Battletech that does not touch crit space, tonnage, and BV only minimally. I use it in Megamek especially).

BV is definitely not the way to go here. The problem with balancing via BV is that you're trying to use a second system to patch a broken first system. As such, it's easy to find and expose flaws with BV. It's better to correct the broken system in the first place--that is how the weapons balance and operate in reference to each other and within the mech design rules.

I took my inspiration directly from what is quoted numerous times about the Clans in the fiction--they load up on expendables for assaults because they expect a quick victory, and expendables supposedly hit harder. Well, in the current balance they largely don't, but in mine they actually do--at the cost of running out of ammo and other issues.

ACs:

First, take the optional rapid fire rule and make it function similar to how Ultra and MASC work now. Perma jam on 3, and since the AC's aren't made to fire sustained, next failure is 5, next is 8, etc.

AC2: 8/16/24/(32) range brackets, 2 damage, 0 heat, no min range. 70 shots per ton.
AC5: 6/13/21 range brackets, 5 damage, 1 heat, no min range. 28 shots per ton.
AC10: 5/11/18 range brackets, 10 damage, 2 heat, no min range, 14 shots per ton.
AC20: 3/7/12 range brackets, 20 damage, 4 heat, no min range, 7 shots per ton.

In my extensive playtesting experience, this helps AC in comparison to their energy contemporaries tremendously and gives good reason to use them.

AC2: It's still a relatively weak niche weapon, but in IntroTech it at least has a unique niche. Removing the silly min range as well as heat helps to pair it with other weapons where it can at least be properly supplementary to them (Blackjack and Jagermech, as examples).

PPC vs AC5: The AC5 has a longer long range that can bracket well with LRMs and the lack of min range helps it stack as a heat efficient pairing to medium lasers and other small weapons. This helps make designs that utilize it in such a mix like the Zeus and Shadow Hawk make a lot more sense. The PPC is still both more efficient and scarier, even with the occasional rapid fire from the AC5, but the AC5 is much more flexible. This helps offset the ammo kabooms and running out of said ammo.

AC10 vs Large Laser: The AC10 packs a bigger bunch out to ranges that can pair alongside the PPC (Banshee 3S as one possibility where this makes sense). The minor heat drop, the occasional rapid fire, and the slight range increase are really all this needed to be a bit more competitive with the large laser (one of them still goes boom and runs out of ammo, the other doesn't).

AC20 vs Medium Lasers: Even with the heat adjustment medium lasers are still more efficient within the first 10 heatsink range, but beyond that the AC20 starts to catch up. To counteract the kabooming and such, the AC20 likewise gets a longer (unoccupied in 3025!) range bracket for mid and long. Also, even if it's still not winning in terms of actual efficiency, the possibility that the AC20 can potentially double tap on you puts the proper fear of our based RNG god into people.

These changes then carry over into Ultras, with Ultra's getting a touch more range at the expense of tonnage and heat. Ultra mode simply changes where the fail on 2 is a jam you can clear. I think my IS Ultras look something like:

UAC2: 8/17/27/(36), 2 damage, 0 heat
UAC5: 7/14/21(28), 5 damage, 1 heat
UAC10: 6/12/18, 10 damage, 3 heat
UAC20: 4/8/12, 20 damage, 6 heat

Or something like that, I don't have it right in front of me.

Anyhow, I can extrapolate more on this. Or I might already have somewhere else.

[RunandFindOut]

Those are very good house rules.  Better than messing with the weight and crits like I have done.  Consider it swiped.

[Empyrus]

Aposiopesis
How do LB-Xs change if at all? Or RACs? And what about ClanTech? Class-2 ACs are kinda terrible regardless of type.

[RunandFindOut]

I know that my solution tends to be getting rid of LB-X autocannons and just giving ordinary AC a cluster shell that does the same thing.

[Empyrus]

That leads to weight/crit changes.
Not an option i'd take. Otherwise one might as well overhaul everything.