Balancing ACs, LRMs, and energy weapons in 3025. Or, justifying the AC/5.

[monbvol]

I'll take the LRM for +0 against ground targets and the LB-2X for +1 against flying targets and with the same specialty ammunition sure it is only +3 at Long Range but considering how many units that mount an AC-5 and more than one ton of ammunition I'll take the trade off versus guessing wrong about what kind I need to bring.  That is without TAG and with Line of Sight or C3.  For AA work I will admit that the AC-2 does do this specialty role very well due to it's sheer reach in 3025.

For killing infantry at 18 hexes or better I'll again take the LRM which I can kill a lot of infantry with the same specialty ammunition as I was using above for the +0 at Long Range.  And if we're talking best case scenario I can bag up to 16 versus the best case scenario of 10 for an AC-5.

While I may not get a +2 on any critical checks that AP ammunition does against reflective armor I can keep using the same ammunition as I was above and do double damage.  Considering that an AC-5 using AP ammunition is still only doing 5 damage and still at a -1 on the roll despite the bonus I'll take sloughing it off twice as fast without taking the +1 to hit making my shot less likely to hit in the first place.

Considering that is three different scenarios I've either outright beat the benefits of the specialty ammunition available to the AC-5 that would have taken three different specialty ammunition types to achieve without having to switch from one LRM specialty ammunition I'd say the AC-5 is looking pretty grim.

And if I really want to eliminate night time penalties that is what they make illumination rounds for.  Which are also available in 3025.

The AC-5 is a piss poor generalist weapon and if you guess correctly about what kind of specialty ammunition to bring it is at best a mediocre specialist weapon.

If you want to disregard Mine Clearing specialty LRM ammunition I suppose I could instead go for Thunder or one it's relatives for doing horrible things to ground targets and stay entirely in Total Warfare while performing close enough even in the face of Tactical Operations specialty ammunitions for ACs and have the benefit of even doing it without Line of Sight to call it a day.

[FedComGirl]

How many have more than one ton of LRM ammo compared to how many with more than one ton of AC ammo?

LRM Flare rounds do no damage. AC Tracer rounds reduce their damage by 1. They do illuminate more area/targets but again 0 damage. And if you've just got the 1 ton...   Flare rounds also aren't available in 3025. Tracer rounds are, although they're harder to find.

You're also presuming the average amount of missiles will hit every time. While average is more often than not it isn't a constant unless you're using aerospace craft. They'll be bad rolls and good ones. And even those may not come out to be average as there's bad dice days and good dice days.  AC's also have more ammo per ton. While you can replace AC-5 with a LRM-10 and carry more ammo- You have to to have the same number of shots. - you're also making a bigger bomb.

It also ignores AMS. While not much of a concern in 3025 against ground units, aerospace craft can use other weapons as point defense. I'd argue all units should be able to but that'd really be getting off topic. Still, earlier and later periods do have AMS which would reduce missile weapons effectiveness.

[monbvol]

My answer to that is two fold.  A: More units mounting LRMs have more than one ton of ammunition than units mounting AC-5s, or ACs in general.  B: With one type of specialty ammunition I'm performing better or close enough to three different types of AC specialty ammunition that even when I only have one ton to work with I'm not guessing wrong hardly ever.

Flare LRMs may not be available in 3025, nor Thunder, but Illumination rounds for Artillery are as are tube artillery.  Or I could instead use Inferno SRMs.  Point is if I want to eliminate a +1 darkness modifier bad enough I also have plenty of ways to go ahead and eliminate the whole +2(for full on darkness) if I want while I'm at it.

We've been over the whole average thing before.  Something new for you to consider though is that there is no rolling for Thunder or for Mine Clearance ammunition on the Cluster hit chart.  Still though iff you have a better number to use I'm willing to entertain it.  While ACs have more ammunition per ton LRMs have more potential damage per ton.  So no you don't have to have the same number of shots to do the same damage or more.  And I've never been particularly afraid of ammunition explosions.

We've also been over the AMS thing.  It is a counter but it is comparatively rare.  Plus it does nothing against Thunder or Mine Clearance ammunition since neither ammunition type attacks a unit and AMS only activates on a successful to hit roll against the carrying unit.

[ialdabaoth]

Honestly, Mine Clearance LRM rounds are the best thing that ever happened to missiles.

[monbvol]

Indeed they are.  Frankly they are so good that I've actually been avoiding them until now.

[FedComGirl]

My answer to that is two fold.  A: More units mounting LRMs have more than one ton of ammunition than units mounting AC-5s, or ACs in general.  B: With one type of specialty ammunition I'm performing better or close enough to three different types of AC specialty ammunition that even when I only have one ton to work with I'm not guessing wrong hardly ever.

A: More ammo equals a bigger bomb. Not that I wouldn't have more ammo if possible. I'm just saying there's more chances to blow up. B: Quite probably true but the availability of specialty ammo varies. For both but more so for the LRM. C: Why is that? Just good at guessing? Spies in the enemy camp? Bribing the GM? Some other reason?

Flare LRMs may not be available in 3025, nor Thunder, but Illumination rounds for Artillery are as are tube artillery.  Or I could instead use Inferno SRMs.  Point is if I want to eliminate a +1 darkness modifier bad enough I also have plenty of ways to go ahead and eliminate the whole +2(for full on darkness) if I want while I'm at it.

Now we're bringing other weapons into again. Your argument that LRMs are better than AC/s fails if you have to bring in other weapons and units.

We've been over the whole average thing before.  Something new for you to consider though is that there is no rolling for Thunder or for Mine Clearance ammunition on the Cluster hit chart.  Still though iff you have a better number to use I'm willing to entertain it.  While ACs have more ammunition per ton LRMs have more potential damage per ton.  So no you don't have to have the same number of shots to do the same damage or more.  And I've never been particularly afraid of ammunition explosions.

Mine Clearance Missiles do 1/4 damage. Nice easy math but your LRM-20 only does 5 points of damage and has only 6 shots. They also can't be targeted at units only hexes. It's can still be damaging but only if I have units in that hex. Thunder LRMs can also be problems but they also can only target hexes and don't do any damage to a unit walking out of the hex. And both ammunition types cost 4 times as much. So you've got 12 rounds of ammunition that cost as much as 48, fired at hexes you hope I'll be in while my AC/5 has 20 shots and they're all firing directly at you.

We've also been over the AMS thing.  It is a counter but it is comparatively rare.  Plus it does nothing against Thunder or Mine Clearance ammunition since neither ammunition type attacks a unit and AMS only activates on a successful to hit roll against the carrying unit.

True, but in that same time period were AMS is comparatively rare. You LRM ammunition is just as rare or hasn't been introduced yet. And there's still point defense which can be argued should be available to ground units.

[monbvol]

A: If I'm doing things right it won't matter that much.  B: Availability of AP is E.  Flak E or F depending on era.  Flechette E.  Precision E.  Tracer D, E, F depending on era.  Mine Clearance E.  Thunder(basic) E F D.  The other Thunder types all E except for Inferno at D.  So The good LRM specialty ammunitions are just as available or more available than AC special munitions.  C: Mine Clearance and Thunder because of how they work are always attacking hexes not units.  If I guess I'm going to be fighting Hovercraft and instead I'm fighting Battlemechs the effectiveness of Mine Clearance or Thunder has not been diminished.  With an AC if I guess I'm going to be fighting VTOLs and instead face Battlemechs the Flak ammunition I loaded up is very much reduced in usefulness to me.  That's how I'll hardly ever guess wrong.  I can load one type of specialty ammunition for LRMs and it still be useful in a wider array of combats than I can get from needing at least three different types of AC specialty ammunition.

My argument isn't that solely LRMs are better than ACs.  My argument is that ACs are frankly borderline crap in the face of existing alternate choices, even in 3025.  LRMs are just one aspect of that.  They have the range to compete against the AC-2 and AC-5.  The only three things they cannot do as well or better on their own are AA(any era), fight in the dark(while incendiary isn't quite as useful as Inferno I can still use it to start a brush fire or something to provide some back lighting to eliminate darkness mods so only during it's extinct period), and kill infantry(only during extinct periods for Thunder and/or Mine Clearance).

Considering there is no flight time and I won't be wasting the ammunition without either LOS or a spotter, or in the case of Thunder have a plan about where I want to put mines to funnel your movement, I'm not sure how I'll ever be wasting ammunition.  And while yes it may only do 5 damage for an LRM-20 against mechs and combat vehicles it is area effect damage.  So buildings and Infantry will take 10.  Unless the Infantry is in the open and thus take 20.  That also includes Battlearmor.

Availability may have gone up but the frequency of mounting it has not kept up with mechs that mount LRMs.  I grant it is a counter but it isn't one that has been embraced.  If we want to stay away from customization it is a lot easier to find a unit mounting one or more LRM than it is to find a unit mounting 1 or more AMS.

[Bismarck]

the characteristic distance down range, that a round will reach, scales as:

range = mass of bullet / (density of air x aerodynamic cross-section of bullet) = m / p_airA

R p_air A = m

i.e. range = that distance through the air, which accumulates one bullet's worth of air mass

approximately, bullets are cylinders, so the mass = area x length x density = A L p_bullet

so...

R ~= (p_bullet / p_air) x L

e.g. a 120mm DU round density ~= 20,000 kg/m3 and a length of nearly ~= 1m...

so, in SI units,

R ~= (20,000 / 1) x 1 = 20,000m = 20km

(Of course, in the 10-15seconds flight time to that range, the round will get gripped by gravity, and droop down ~= 1000m... you'd only get to 20km on an indirect fire type of trajectory)

So, range is determined by the size / shape of the round

range = round

Meanwhile, damage = KE = 1/2 m v_muzzle² = due to gun

damage = gun



if you snub a barrel, then all you do is reduce the distance / time that the gun charge can accelerate the round... you reduce the muzzle velocity, and damage done... but once the bullet leaves the barrel, it will dissipate that whatever amount of energy, through the same characteristic distance (albeit slower rounds will droop more thru the same distance down range)

the only way to have high damage, and low range, would be to lob an enormous mortar round, which would squash whatever it landed on, but cannot proceed far afield

sawing off a barrel would reduce damage done (and direct fire range)... an AC/20 couldn't do high damage, with a short barrel, and low muzzle velocity

high damage x low range = game balance (?) != realism... unless you are essentially saying that they have long minimum ranges, b/c of slow traverse, b/c BMs cannot lug the loads well... e.g. battleship turret cannons can fire miles, but couldn't quickly track targets close in

so if BMs can barely lift AC/20s, and barely swing them side-to-side, then that would affect range... even then, AC/20s would have a huge range, w/ an almost-as-huge minimum range, something similar to ER-LRMs, they could fire 40 hexes, but BMs couldn't twist & turn to track targets, so they'd have a minimum of 20 hexes (say)

juggling the equations, to explain high damage x low range is not really potentially possible... if anything, AC ranges out to be reversed, bigger guns fire farther afield, but can't track targets close to the carrier of the cannon

[Bismarck]

surviving the BT battlefield = speed (don't get hit) x armor (w/stand hits) x range (reach the other guy)

3025 light 'Mechs must sacrifice armor for speed... if they must also sacrifice range, then they cannot compete... you sacrifice all weapons and armor, for 8/12 movement... but then have to close to point blank range... you might give the other guy +3/+4 on target modifiers, but his range penalty ----> +0, whilst yours could still be +2/+4...

retcon'ing light AC's, and light PPCs, would theoretically give 3025 light 'Mechs the option, of only sacrificing armor, for mobility, plus range too

e.g. 40 ton Assassin w/ 2xL-PPC could dominate the discussion on range, whilst also winning on mobility too...
7/11/0 w/ 128 armor + 2xL-PPCs = super-fast mini-Marauder

w/ a good pilot, a 40 ton 'Mech such as that could come close to competing equally

low-mass LR weapons + (perhaps) some system for advantaging smaller 'Mechs for their smaller profiles + (perhaps) initiative advantage b/c smaller 'Mechs are more mobile & readily reacting & responsive (e.g. all ties on initiative ----> lighter mass 'Mech)

would (re-)balance the game to make more 'Mech mass brackets battle-worthy (to give 3025 more to work well with)

(smaller 'Mechs have smaller profiles => to-hit penalty... would only be fair, if the optional rule, for reduced crits for smaller 'Mechs was also used simultaneously together too)

[monbvol]

Honestly the only weapons I can understand having minimum ranges without creating disconnects have always been PPCs and Gauss Rifles.  LRMs I could understand if they used my house rule of taking a -1 to the cluster hit roll(to a minimum of a result of 2) for each hex of minimum range.  ACs not so much.

[Bismarck]

missiles much accelerate out of their launch tubes...

if they accelerated at (say) 10G = 100m/s/s ...

then the constant-acceleration-equations =>

v² = 2 a d = 6000 m²/s² x # hexes

v ~= 80m/s x #hexes^1/2 ~= 3MP x sqrt(range in BT hexes)

so, out to a range of 1-4-9 hexes...

the missiles would only be moving w/ 3 / 6 / 9 MP

LRM MR's realistically reflect the slow starts of most missiles... a Locust rapidly running right past an Archer would out-run most missiles ...



oops

http://en.wikipedia.org/wiki/Hydra_70

F = m a
6300 N = 6.3kg x a
a = 1000m/s/s = 100G

acceleration = x10 above
velocity = x3.3 above

so most missiles might realistically reach BT map MPs = 9 w/in one hex of the firer, 18 MP @ 4 hexes, 27 MP @ 9 hexes

throw in some air resistance, and requirements for sake of simplicity... one could conceivably claim, that missiles in BT acquire speed at a straight rate, linearly increasing at (say) 8-10 MP per hex... so super-fast units could conceivably come too close to LRM launchers...

SRMs = designed for SR use, they'd accelerate more quickly, (say) +10-15 MP per hex

Clan missiles evidently accelerate quicker still

linear velocity increase w/ range is not strictly realistic... but good enough for a game, conveying the concept

incorporating a few hexes worth of minimum-like-range effect for missiles would add some realism, and add a variable for flexibility

i think missile MRs reflect rockets' "slow starts", and that the MR key concept = missile speed ( MP equivalent ) -- 'Mechs dashing past launchers could conceivably outrun most missiles => to-hit penalty



actually, bigger missiles might accelerate much more slowly... potentially providing a partially-enough plausible pretext, for BM's use of ~10kg rocket-massed munitions

[Bismarck]

w/ repeat rapid ROF (e.g. = 5 per turn), a light AC/2 seems a suitable cannon to carry

e.g. 3025
50 tons
6/9/0
~10 tons armor
~10 tons weapons
2xL-PPC
1xL-AC2

[FedComGirl]

A: If I'm doing things right it won't matter that much.  B: Availability of AP is E.  Flak E or F depending on era.  Flechette E.  Precision E.  Tracer D, E, F depending on era.  Mine Clearance E.  Thunder(basic) E F D.  The other Thunder types all E except for Inferno at D.  So The good LRM specialty ammunitions are just as available or more available than AC special munitions.  C: Mine Clearance and Thunder because of how they work are always attacking hexes not units.  If I guess I'm going to be fighting Hovercraft and instead I'm fighting Battlemechs the effectiveness of Mine Clearance or Thunder has not been diminished.  With an AC if I guess I'm going to be fighting VTOLs and instead face Battlemechs the Flak ammunition I loaded up is very much reduced in usefulness to me.  That's how I'll hardly ever guess wrong.  I can load one type of specialty ammunition for LRMs and it still be useful in a wider array of combats than I can get from needing at least three different types of AC specialty ammunition.

A: If everything went right all the time there'd be no need for CASE. B: Thunder LRM went extinct in 2840 and weren't reintroduced 3052. While its possible some were hoarded away for special use and some could be stumbled upon they're not available for purchase between 2840 and 3052 as they're extinct. The other Thunder LRM types aren't available before they're introductions starting in 3056. Tracer and Flak ammo never went extinct and could still be found.  C: If that type of LRM ammo is available sure they're of use. Otherwise your choices in ammo are limited. Flak Ammo will at least do some damage to mechs. So will tracers. Flares won't.

My argument isn't that solely LRMs are better than ACs.  My argument is that ACs are frankly borderline crap in the face of existing alternate choices, even in 3025.  LRMs are just one aspect of that.  They have the range to compete against the AC-2 and AC-5.  The only three things they cannot do as well or better on their own are AA(any era), fight in the dark(while incendiary isn't quite as useful as Inferno I can still use it to start a brush fire or something to provide some back lighting to eliminate darkness mods so only during it's extinct period), and kill infantry(only during extinct periods for Thunder and/or Mine Clearance).

LRMs do have advantages over AC/s. But that doesn't make AC/s borderline crap. Except for Aerospace, and some specialty ammo, there's no guarantee that all the missiles will hit.  Or even that you will hit every time. While the latter is true for ACs as well they'll do full damage unless you're using alternative damage rules. They'll also have more shots per ton to fire with so a miss isn't as critical to them. If one chooses they could also rapid fire. Risky but it can come in handy and there's no rules against doing so with special ammo and they can fire at multiple targets. AC's can also use Tracers to fight at night and use Flak against infantry.

Considering there is no flight time and I won't be wasting the ammunition without either LOS or a spotter, or in the case of Thunder have a plan about where I want to put mines to funnel your movement, I'm not sure how I'll ever be wasting ammunition.  And while yes it may only do 5 damage for an LRM-20 against mechs and combat vehicles it is area effect damage.  So buildings and Infantry will take 10.  Unless the Infantry is in the open and thus take 20.  That also includes Battlearmor.

That'd be bad news for my Field gun platoons but not so my mechs, and you're presuming you can funnel my movements. That'd really depend on the map and the speed of the unit I'm using.

Availability may have gone up but the frequency of mounting it has not kept up with mechs that mount LRMs.  I grant it is a counter but it isn't one that has been embraced.  If we want to stay away from customization it is a lot easier to find a unit mounting one or more LRM than it is to find a unit mounting 1 or more AMS.

True.  Most units think more in terms of armor and CASE for defense than stopping the missiles from hitting in the first place. And again one can argue for using other weapons for point defense so they might not see the need for a dedicated AMS.

[evilauthor]

the only way to have high damage, and low range, would be to lob an enormous mortar round, which would squash whatever it landed on, but cannot proceed far afield

Actually...

Given that BT weapon ranges are EFFECTIVE ranges (aka, "Can I reliably hit this target I'm aiming at?" and not "Can my weapons fire REACH this distance?"), my pet theory is that heavier ACs are suffering from recoil issues spoiling their aim. AC damage goes up (more or less) linearly while AC WEIGHT does not. This suggests to me that there's comparatively less mass to absorb the recoil of an AC shot the more damage an AC does. And given that ACs are usually depicted as firing bursts of bullets instead of single rounds, this means each bullet in a burst is going to be throwing the AC's aim a little off every time they fire.

In short, more damage => more recoil => less weapon accuracy => shorter effective ranges. At least for ACs.

End result is that heavy ACs have shorter effective ranges than lighter ones. It's not that their bullets can't reach farther. It's that if they try hitting farther out, their bullets are going to fly wide of the target because recoil is throwing their aim off.

Notably, rifle canons and Gauss Rifles have comparable or better range, and they're fluffed as firing single projectiles per shot. If it weren't for the damage nerf, I'd take a rifle cannon over an AC any day.

[monbvol]

A: If everything went right all the time there'd be no need for CASE. B: Thunder LRM went extinct in 2840 and weren't reintroduced 3052. While its possible some were hoarded away for special use and some could be stumbled upon they're not available for purchase between 2840 and 3052 as they're extinct. The other Thunder LRM types aren't available before they're introductions starting in 3056. Tracer and Flak ammo never went extinct and could still be found.  C: If that type of LRM ammo is available sure they're of use. Otherwise your choices in ammo are limited. Flak Ammo will at least do some damage to mechs. So will tracers. Flares won't.

A: AC ammunition explosions are just as bad during CASE's abscence.  I can fill a graveyard with the mechs I've lost to AC ammunition explosion.  Probably pretty close to the same for LRM ammunition explosion.  Bottom line bemoaning ammunition explosion isn't that relevant.  B:  I already addressed that.  C: Since it is just as available as any of the AC ammunitions during the listed dates or more available I'm not sure how this is an issue.  While illumination rounds do not do damage they will completely eliminate all darkness modifiers.  Tracers don't.  Since none of my alternatives are reduced to half damage without my opponent taking mutually exclusive armor types I'll take the alternatives.

LRMs do have advantages over AC/s. But that doesn't make AC/s borderline crap. Except for Aerospace, and some specialty ammo, there's no guarantee that all the missiles will hit.  Or even that you will hit every time. While the latter is true for ACs as well they'll do full damage unless you're using alternative damage rules. They'll also have more shots per ton to fire with so a miss isn't as critical to them. If one chooses they could also rapid fire. Risky but it can come in handy and there's no rules against doing so with special ammo and they can fire at multiple targets. AC's can also use Tracers to fight at night and use Flak against infantry.

We've been over the no guarantee thing.  Plus I'll grant that LRMs by themselves don't make ACs near useless crap.  Combined with all the other alternatives though they just do not compete.  I have granted that for a time period the AC-2 and AC-20 do offer things that can't be matched by other weapons but even then the weight I'm investing in them leaves little room for anything else.

That'd be bad news for my Field gun platoons but not so my mechs, and you're presuming you can funnel my movements. That'd really depend on the map and the speed of the unit I'm using.

And how would your mechs not be hit?  Your statement comes across as if you believe you can move your mechs in the time Mine Clearance munitions are fired and resolved.  This is not the case.  Seems you are also making a similar assumption about Thunder.  It doesn't matter how fast your mechs are or what kind of map it is.  I will be doing damage or making hexes unattractive to enter.

True.  Most units think more in terms of armor and CASE for defense than stopping the missiles from hitting in the first place. And again one can argue for using other weapons for point defense so they might not see the need for a dedicated AMS.

The ultimate bottom line is AMS counters but six(LRMs, SRMs, MRMs, ATMs, Thunderbolt, NARC) tools in the very large box of tools that I can dig into for instead of ACs and I do have tactics and methods to make those six tools not have to worry about AMS.  I can even use force selection to achieve such tactics and methods so I don't even have to use the customization card.

[HazMeat]

Actually...

Given that BT weapon ranges are EFFECTIVE ranges (aka, "Can I reliably hit this target I'm aiming at?" and not "Can my weapons fire REACH this distance?"), my pet theory is that heavier ACs are suffering from recoil issues spoiling their aim. AC damage goes up (more or less) linearly while AC WEIGHT does not. This suggests to me that there's comparatively less mass to absorb the recoil of an AC shot the more damage an AC does. And given that ACs are usually depicted as firing bursts of bullets instead of single rounds, this means each bullet in a burst is going to be throwing the AC's aim a little off every time they fire.

In short, more damage => more recoil => less weapon accuracy => shorter effective ranges. At least for ACs.

End result is that heavy ACs have shorter effective ranges than lighter ones. It's not that their bullets can't reach farther. It's that if they try hitting farther out, their bullets are going to fly wide of the target because recoil is throwing their aim off.

Notably, rifle canons and Gauss Rifles have comparable or better range, and they're fluffed as firing single projectiles per shot. If it weren't for the damage nerf, I'd take a rifle cannon over an AC any day.

In my personal headcanon, autocannon projectiles carry an unspecified active payload because that was already to be expected of contemporary autocannon when BT was first conceived, let alone a far-flung future.  That aside, if you prefer the plain old bullet approach, I think recoil may be a good place to look for at least part of an explanation for the odd stats.  IF damage can sometimes have more to do with momentum than energy, which is probably suggested by falling and melee attack damage, then it fits alright since lower-velocity bullets carry more momentum (and thus generate more recoil to skew up your volley placement) in proportion to the energy they carry than high-velocity bullets do. 

[Bismarck]

damage per ton is a good observation...

personally i perceived that, somewhat similar to the "nerf" of rifles, BT armor was so "space age" that there was considerable "over-head" before bullets began doing damage (more than mere chipping out of chunks)...

i plotted the gun tonnage vs. caliber, from TRO1945...

T ~= C^2.4

inexpertly, i'd deduce damage

D ~= C³⁺

since bigger bullets are bigger every which way, bullet density is probably close-to-constant ("they're all DU"), so bullet mass = rho x C³... and bullet KE = mass x v_muzzle² x 0.5

bigger guns generate higher muzzle velocities... even in the absence of which, damage would be proportional to mass, prop. to caliber cubed...

so, i'd deduce damage per ton

D/T ~= C^0.6+

and so, i don't invoke "recoil" to explain perfectly-plausible-(apparently)-presently increasing D/T ratios, for BT ACs (astute observation tho')



the fluff says GR have ">2x" the muzzle velocity of conventional cannons => >4x damage per projectile...
(which would amount to 3-4+ km/sec)

GR ~= 3-to-4-point AC single-slug bullet x4

3-to-4-point AC bullet ~= "medium rifle", which gets 9 rounds per ton ~= GR

and, MR ~= 100mm AC, estimating from TRO1945

(LR ~= 75mm, MR ~= 100mm)

i would guess that a MR ----> "medium AC" = AC/5 or AC/10...
(the TRO1945 "borderline MR" = 88mm = 40 rounds per ton... full-fledged "medium AC" = 100mm = 20 rounds per ton sounds similar to single-slug shots...)

i'd opt for the former, if you say ACs = single shot semi-auto, or the latter, if you say ACs = bursts of 3-5 rounds
(if you look online for pix of tank gun-cannons firing, then you'll see that a single slug shot = enormous amount of energy, producing a blast as big as a broadside from some sailing ship... i have a hard time imagining ACs on full-auto... the recoil would waste the second and subsequent shots, which would also ricochet off of any discarded sabos... and all the extra recoil compensation would amp the mass an enormous amount)

considering 'tis a game, all the numbers come comparatively close to equating

i'd guess AC/5 ~= GR ~= 100mm
(i personally perceive, that all BT guns receive unrealistically few rounds per ton of ammo... the Abrams 120mm ~= "heavy rifle" ~= AC/10 (?) gets ~40-50 rounds per ton, w/ DU dart ammo)

[Bismarck]

trying to help "dueling" optional rules...

which would amp up AC ROF

but people possibly perceive that "120-pt heat scale" as cumbersomely new-and-different...

stick w/ standard 30-point scale...
game turns occur in "lots of four"
BM heat dissipation gets divided into fourths, evenly as possible w/o complexity

e.g. 10 HS ----> 3/3/2/2 heat per turn

everything else is normal, except for "duration heat" FX such as moving, standing in fire, or water, etc.

for those, since game turns = 1/4th the duration, heat gained/lost = 1/4th...

how to account for partial heat points ?

game turns occur in groups of four...
at the beginning of some "first of four" turns, everybody clears out a heat pool...
every time they walk, add one counter of some sort, to the pool...
run => add 2
etc.

every time you see 4 heat counters in your pool, remove the 4, and increment heat by 1
water would also allow you to remove heat counters

after every fourth turn, the heat pool is cleared out, repeat

that way, AC/2s could fire for less than one HP, and partial HP could be accounted, w/o using newfangled 120HP scale

(one heat counter = 1/4th HP)

[FedComGirl]

Actually...

Given that BT weapon ranges are EFFECTIVE ranges (aka, "Can I reliably hit this target I'm aiming at?" and not "Can my weapons fire REACH this distance?"), my pet theory is that heavier ACs are suffering from recoil issues spoiling their aim. AC damage goes up (more or less) linearly while AC WEIGHT does not. This suggests to me that there's comparatively less mass to absorb the recoil of an AC shot the more damage an AC does. And given that ACs are usually depicted as firing bursts of bullets instead of single rounds, this means each bullet in a burst is going to be throwing the AC's aim a little off every time they fire.

In short, more damage => more recoil => less weapon accuracy => shorter effective ranges. At least for ACs.

End result is that heavy ACs have shorter effective ranges than lighter ones. It's not that their bullets can't reach farther. It's that if they try hitting farther out, their bullets are going to fly wide of the target because recoil is throwing their aim off.

Notably, rifle canons and Gauss Rifles have comparable or better range, and they're fluffed as firing single projectiles per shot. If it weren't for the damage nerf, I'd take a rifle cannon over an AC any day.

I think it's partially the recoil reducing accuracy like you said. But it's also that since AC/s are firing bursts the ammo has had to reduce propellant and the size/weight of the round to fit as many rounds in per ton. An AC/20 firing 10 round bursts carries 50 rounds per ton. A Heavy Rifle Cannon the same size only carries 6. I think that has to have some effect on the weapons range and damage.

A: AC ammunition explosions are just as bad during CASE's abscence.  I can fill a graveyard with the mechs I've lost to AC ammunition explosion.  Probably pretty close to the same for LRM ammunition explosion.  Bottom line bemoaning ammunition explosion isn't that relevant.  B:  I already addressed that.  C: Since it is just as available as any of the AC ammunitions during the listed dates or more available I'm not sure how this is an issue.  While illumination rounds do not do damage they will completely eliminate all darkness modifiers.  Tracers don't.  Since none of my alternatives are reduced to half damage without my opponent taking mutually exclusive armor types I'll take the alternatives.

A:True. However, having more than one ton of ammo increases the chances of suffering an ammo explosion. And to have the same number of shots  as the lighter AC/s you have to have more than one ton. 

B: Production Dates take precedence over Availability Ratings.

C: See B. And Tracers only reduce the damage by 1 point so only the AC/2 will have it's damage reduced by half. The AC/5 will be reduced to 4 points. And 4 points is still more than 0. 0 is how much damage Flares do. There do have tactical uses but they won't damage the enemy by themselves.

We've been over the no guarantee thing.  Plus I'll grant that LRMs by themselves don't make ACs near useless crap.  Combined with all the other alternatives though they just do not compete.  I have granted that for a time period the AC-2 and AC-20 do offer things that can't be matched by other weapons but even then the weight I'm investing in them leaves little room for anything else.

I agree that their weight is an advantage as they can be combined with others. But that depends on what they're combined with, and what they're combined on.

And how would your mechs not be hit?  Your statement comes across as if you believe you can move your mechs in the time Mine Clearance munitions are fired and resolved.  This is not the case.  Seems you are also making a similar assumption about Thunder.  It doesn't matter how fast your mechs are or what kind of map it is.  I will be doing damage or making hexes unattractive to enter.

I didn't say they wouldn't be hit. Just that 5 points of damage doesn't effect them as much as 10 points will to infantry. And while Thunder can make hexes unattractive and damaging to enter, they only do wo when Thunder Ammo is available. And it isn't in 3025.

The ultimate bottom line is AMS counters but six(LRMs, SRMs, MRMs, ATMs, Thunderbolt, NARC) tools in the very large box of tools that I can dig into for instead of ACs and I do have tactics and methods to make those six tools not have to worry about AMS.  I can even use force selection to achieve such tactics and methods so I don't even have to use the customization card.

And Rockets?   AMS isn't the only counter to them. And your bringing other things in again. Bringing in other units and the tactics and methods goes to the skill and luck of the player. Not the capability of the weapon.

[monbvol]

A: Looks like you want to go in circles on this point so I'll stop my end of it now.

B: Okay let's look at those intro dates then.  AP 3059.  Flak 2310.  Flechette 3055.  Precision 3062.  Tracer 2300.  Thunder(standard) 3052.  Thunder Active 3058.  Thunder Augmented 3057.  Mine Clearance 3069.  Incendiary LRM 2341.  Inferno 2341.  Illumination rounds for tube artillery Pre Spaceflight.  So I might have to wait a few years for Mine Clearance and the other Thunder types but with what I can do with Thunder(standard) that makes it just as effective as three different types of AC specialty ammunition I think I can have the patience.

C: Considering all of my options I'll take that trade off.

It doesn't matter what the ACs are combined with or on.  Their sheer weight ensures that you will have an overly specialized unit that at best can do other roles in a token manner.

Then the 5 points of AC-5 damage isn't a big deal either.  5 points is 5 points.  Can't dismiss the damage as meaningless without dismissing it as meaningless for all weapons that do 5 points of damage.

I can't believe I forgot rockets.  Lovely things those.  Still doesn't change the fact that the tools are there and it doesn't even take extra ordinary luck or skill to make use of them, nor does it take that many to perform everything that ACs do close enough or better, and if I do guess wrong about what kind of foe I'll be facing I still maintain that yes I may have a more difficult fight ahead of me than I anticipated but it will not be nearly as difficult as if I had guessed wrong with ACs.

[FedComGirl]

A: Looks like you want to go in circles on this point so I'll stop my end of it now.

It just strikes me as odd that I keep reading about certain mechs with AC/s having ammo bombs when one of the advantages of LRMs lighter size is that they can have more ammo, thus creating a bigger bomb.

B: Okay let's look at those intro dates then.  AP 3059.  Flak 2310.  Flechette 3055.  Precision 3062.  Tracer 2300.  Thunder(standard) 3052.  Thunder Active 3058.  Thunder Augmented 3057.  Mine Clearance 3069.  Incendiary LRM 2341.  Inferno 2341.  Illumination rounds for tube artillery Pre Spaceflight.  So I might have to wait a few years for Mine Clearance and the other Thunder types but with what I can do with Thunder(standard) that makes it just as effective as three different types of AC specialty ammunition I think I can have the patience.

You'll have to wait for all Thunder types. Thunder went extinct in 2840 and won't be reintroduced until 3052. Unless you find some long lost stockpile. Which is possible however unlikely. And you're bringing in other weapons again.

C: Considering all of my options I'll take that trade off.

Your other options being?

It doesn't matter what the ACs are combined with or on.  Their sheer weight ensures that you will have an overly specialized unit that at best can do other roles in a token manner.

I meant the LRMs and the same can be said of a unit with a LRM-15 with 2 tons of ammo. And that's for a unit that's not worried about heat. For a unit that does worry about heat even a LRM-10 ends up weighing as much as a AC/5.

Then the 5 points of AC-5 damage isn't a big deal either.  5 points is 5 points.  Can't dismiss the damage as meaningless without dismissing it as meaningless for all weapons that do 5 points of damage.

I didn't say it was meaningless. But its less worrying when you're trying to hit a hex I might be in when all my ammo's going directly at you.

I can't believe I forgot rockets.  Lovely things those.  Still doesn't change the fact that the tools are there and it doesn't even take extra ordinary luck or skill to make use of them, nor does it take that many to perform everything that ACs do close enough or better, and if I do guess wrong about what kind of foe I'll be facing I still maintain that yes I may have a more difficult fight ahead of me than I anticipated but it will not be nearly as difficult as if I had guessed wrong with ACs.

Aren't they :)   There are tools that can give LRMs a possible advantage but again that depends on what it's mounted on and what else might go with it. Some of those advantages depend on other things. Without them the advantage they have over AC/5 is range. Some also have the possibility of more damage. But that's only a possibility and they still have less ammo.

[Bismarck]

range is proportional to the length of the bullet; and, if bullets' shapes scale proportionally, then the length is proportional to the caliber:

R ~ C

meanwhile, mass scales as the caliber to the ~5/2 power

M ~ C^2.5

if you prefer bursts, they seemingly consist of circa 4 rounds each:

Code: [Select]

kind     caliber        heat     range       tons       slugs per ton
AC-1       50mm         0.25-      9           2             400
AC-2       75mm         0.5-      15-          4             200
AC-5      100mm          1        18           8              80
AC-10     125mm          3        21+         12              40
AC-20     150mm          7        27          18+             20
tangentially, per the video games, and to emphasize the potence of more massive weapons:

Code: [Select]

kind     damage       range       tons
Sm.Lsr      2           8         0.5
Md.Lsr      4          12          1
Lg.Lsr      8          16          5

[Bismarck]

another thread suggests AC/1s...

AC/1 ~= 50-60mm, realistically about the minimum conceivable cannon calibre


(separately, if the Abrams 120mm cannon = SMOOTH bore, then hypothetically AC's = smooth bore too)

[tomaddamz]

range is proportional to the length of the bullet; and, if bullets' shapes scale proportionally, then the length is proportional to the caliber:

[snip, see above]

You are assuming the same initial velocity for all AC rounds, this is not necessarily true.  The fluff at best is contradictory and shows little appreciation for projectile-target interaction.  It would be easier to explain the AC/20 as similar in function to the Royal Ordnance L9, and something smaller like the AC/2 more like the Shipunov 2A42 or a Alliant Techsystems Mk 44.  The other thing this would allow one to believe is that there are different defeat mechanisms involved for different sized auto cannon and their respective ammunition types.

With that said, the AC/5 is pretty much worthless as a anti-Mech weapon, at best it is an overweight support weapon, that with specialized ammo can perform some battlefield roles more cost effectively than LRM systems ( anti-PBI especially), but does not have the crunch power to stop even a light mech, nor the standoff range to reliably hit targets and not receive a massive and unequal retaliation.

[monbvol]

It just strikes me as odd that I keep reading about certain mechs with AC/s having ammo bombs when one of the advantages of LRMs lighter size is that they can have more ammo, thus creating a bigger bomb.

More mechs with LRM ammunition, even if they have more of it, have something besides LRM ammunition with their LRM ammunition.  Note I'm not saying all.  I haven't forgotten egregious examples like the 3R Crusader.  Still though an ammunition bomb is an ammunition bomb.  Though where the LRM advantage does come in is in the fewer shots per ton.  It takes fewer turns of firing for me to reduce the threat and considering I'm doing more damage more often than not I'll take that exchange.

You'll have to wait for all Thunder types. Thunder went extinct in 2840 and won't be reintroduced until 3052. Unless you find some long lost stockpile. Which is possible however unlikely. And you're bringing in other weapons again.

I don't have to wait for Thunder as long as I'd have to wait for AP, Flechette, or Precision.  And I had already talked about Illumination rounds, Incendiary rounds, and Inferno rounds so for completeness I included them.

Your other options being?

The ones I talked about a few times now.  Since you want to talk specific eras I will admit my tools do have to change but it doesn't stop me from having different tools.

I meant the LRMs and the same can be said of a unit with a LRM-15 with 2 tons of ammo. And that's for a unit that's not worried about heat. For a unit that does worry about heat even a LRM-10 ends up weighing as much as a AC/5.

In 3025 the LRM-10 will kill more infantry(no rolling on the cluster table needed).  Even if I roll minimum all the time(which I won't) I'll be nearly as dangerous to mechs and vehicles.  Sure I can't get the -2 of Flak against flying targets but then I've admitted several times that I actually give some respect to the AC-2s sheer range for this role.  Tracer ammunition only eliminates a +1 darkness modifier.  Overall I'd take my chances with the LRM-10 if I had my choice between the two.

I didn't say it was meaningless. But its less worrying when you're trying to hit a hex I might be in when all my ammo's going directly at you.

This comment still indicates you do not understand how Mine Clearance specialty ammunition works.  There is no hex you may be in.  There is no moving out of the way between the time the ordinance leaves the launcher and the attack against the hex is resolved.  Your only hope that I do not hit a hex occupied with one of your units is that I fail my to hit roll.  With a -4 immobile target modifier, no defensive movement modifier to worry about, only terrain and attacker movement modifier.

Aren't they :)   There are tools that can give LRMs a possible advantage but again that depends on what it's mounted on and what else might go with it. Some of those advantages depend on other things. Without them the advantage they have over AC/5 is range. Some also have the possibility of more damage. But that's only a possibility and they still have less ammo.

LRMs by themselves without any other tools do a dang good job of making AC-2s and AC-5s poor weapon choices at all.  I may not always replace AC-2s and AC-5s with LRMs of some type but in a side by side comparison it's hard for me to not side with the LRMs because they offer greater versatility without having to resort to specialty ammunitions, have better than 50% odds of doing more damage each time they hit without resorting to any other tools, and when comparing the capabilities of specialty ammunitions LRMs can use fewer types to maintain their versatility edge over the AC-2 and AC-5.

[Bismarck]

[snip, see above]

You are assuming the same initial velocity for all AC rounds, this is not necessarily true....

i'm not assuming anything... the range of a round is related to the round's own aerodynamic shape...

muzzle velocity => KE = damage...

but the rate at which the round reduces in speed / energy depends upon the round only

[FedComGirl]

More mechs with LRM ammunition, even if they have more of it, have something besides LRM ammunition with their LRM ammunition.  Note I'm not saying all.  I haven't forgotten egregious examples like the 3R Crusader.  Still though an ammunition bomb is an ammunition bomb.  Though where the LRM advantage does come in is in the fewer shots per ton.  It takes fewer turns of firing for me to reduce the threat and considering I'm doing more damage more often than not I'll take that exchange.

True fewer shots per ton is an advantage in a ammo bomb. But it's also a disadvantage at it's less rounds fired at the enemy. You're also presuming most of all the missiles will hit. That isn't always the case.

I don't have to wait for Thunder as long as I'd have to wait for AP, Flechette, or Precision.  And I had already talked about Illumination rounds, Incendiary rounds, and Inferno rounds so for completeness I included them.

But I can still use standard, tracer, and flak.

The ones I talked about a few times now.  Since you want to talk specific eras I will admit my tools do have to change but it doesn't stop me from having different tools.

Meanwhile the AC doesn't have to change.

In 3025 the LRM-10 will kill more infantry(no rolling on the cluster table needed).  Even if I roll minimum all the time(which I won't) I'll be nearly as dangerous to mechs and vehicles.  Sure I can't get the -2 of Flak against flying targets but then I've admitted several times that I actually give some respect to the AC-2s sheer range for this role.  Tracer ammunition only eliminates a +1 darkness modifier.  Overall I'd take my chances with the LRM-10 if I had my choice between the two.

Against infantry, sure. But you're being as dangerous to mechs and vehicles isn't a sure thing. 12 minimums is only 36 points. 20 rounds form an AC/5 is 100 points of damage. Presuming a hit every time.

This comment still indicates you do not understand how Mine Clearance specialty ammunition works.  There is no hex you may be in.  There is no moving out of the way between the time the ordinance leaves the launcher and the attack against the hex is resolved.  Your only hope that I do not hit a hex occupied with one of your units is that I fail my to hit roll.  With a -4 immobile target modifier, no defensive movement modifier to worry about, only terrain and attacker movement modifier.

You're still aiming at where I am, or where you hope I'll be.

LRMs by themselves without any other tools do a dang good job of making AC-2s and AC-5s poor weapon choices at all.  I may not always replace AC-2s and AC-5s with LRMs of some type but in a side by side comparison it's hard for me to not side with the LRMs because they offer greater versatility without having to resort to specialty ammunitions, have better than 50% odds of doing more damage each time they hit without resorting to any other tools, and when comparing the capabilities of specialty ammunitions LRMs can use fewer types to maintain their versatility edge over the AC-2 and AC-5.

By themselves they have range and the possibility of more damage. That's it. And while you have the possibility of more damage you have less changes to cause it. You have to use a LRM-15 to  always do as much damage as an AC/5. Without any anti-missile defenses, that is. And you've only got 8 shots unless you add more ammo. If you do that you're now at the same weight as the AC/5, and you still have 4 less shots. You're also generating 5 times the heat.  And not every unit likes heat.

Since you probably have better dice karma than me the LRM-15 probably seems like overkill to you. To me, it's the closest missile equivalent to a AC/5. Hitting with more than the minimum missiles like hitting with both rounds when the AC/5 rapid fires. Without risking a jam.  That doesn't mean I won't use LRM-5s. But I'm not going to be ripping out all my AC/s either.

[tomaddamz]

i'm not assuming anything... the range of a round is related to the round's own aerodynamic shape...

muzzle velocity => KE = damage...

but the rate at which the round reduces in speed / energy depends upon the round only

I guess that makes the RPG-7 pretty near useless considering the only ~375 f/s of muzzle velocity. 

The projectile "Defeat Mechanism" can be independent of the weapons muzzle velocity. 

[Bismarck]

http://bg.battletech.com/forums/index.php/topic,29179.msg673159.html#msg673159

comparing w/ TRO1945:

AC/2 = 50mm ~ ?  = 1 tons
AC/5 = 75mm ~ "light rifle" = 3 tons / 3D / 1H
AC/10 = 100mm ~ "medium rifle" = 5 tons / 6D / 2H
AC/20 = 125mm ~ "heavy rifle" = 8 tons / 9D / 4H

to upgrade, from single-shot cannons, to 3025 BT ACs, requires +5/+5/+7/+6 tons

in TRO1945, caliber, tons, damage, are all proportional, T ~= D ~= C...

if that remained the case for 3025 BT ACs, then their D ~= 5/7/10/12 for the four

(if D ~= C³, then the damages would scale as ~= 1:4:8:16 ----> 2:5:10:20 ?)

Code: [Select]

kind     caliber        heat     range       tons       slugs per ton
AC-2       50mm         0.25      12           2             100+
AC-5       75mm          1        18           4              40
AC-10     100mm          3        24           7              20?
AC-20     125mm          7        30          10              10?


http://www.wwiivehicles.com/ussr/guns.asp

per a plot, penetration scales with caliber, P ~ C

(for all of the Soviet ammo, mass, momentum, and kinetic energy were all proportional, and all proportional to penetration^0.5

m ~ p=mv ~ KE=1/2mv² ~ P^1/2

(very) approximately, all the guns had comparable muzzle velocity)


from seemingly RL stats, penetration ~= damage (?) ~= caliber

if so, then ACs would do ~= 5/7/10/12D for the four

(if those represent bursts of 3-5 rounds, then damage per round would be 1-2 / 2 / 2-3 / 3-4...

that would make some sense, since, first, GR do as much damage as an AC "burst", w/ a single slug, which the fluff says has 4x the KE (2x velocity)...

and b/c "BAR" rules say standard 3025 armor = BAR 10, so every single attack doing >10D gets %crit...

which couldn't occur commonly in 3025 era...

as if AC-20 != 20 single slug damage, but a burst of bullets, dispersing damage, w/o penetrating in a single super-slug)

[Bismarck]

sketch of concept --


BT missiles ~= 10kg rockets (+ "semi" guidance)

similar sizes of missiles' motors generate giant thrust ~= 100Gs... for a second or so

BT missiles = "semi" guided only as long as the motors are making maneuvering potentially possible...

so, hypothetically, BT missiles could be fired out to km's ranges... but past their canon LR, their motors cut out, and they glide on, on ballistic trajectories, as something similar to DFMs, MRMs, rockets in BT



for a constant mass, more fuel => less warhead et vice versa

if you do the math, and use linear approximations, for the sake of simplicity w/ accuracy if not precision...

then the following would be both streamlined and qualitatively accurate:

SRMs = 3 units of damage, 1 unit of range (more warhead, less fuel)
MRMs = 2 units of damage, 2 units of range
LRMs = 1 unit of damage, 3 units of range (more fuel, less warhead)


and, ranges "ought" to be of increasing extent, since missiles are constantly accelerating, so they whizz thru longer range brackets more quickly...

ranges "ought" to come in groups of 1:2:3, e.g.

SRMs = 1-2 / 3-6 / 7-12
MRMs = 1-4 / 5-12 / 13-24
LRMs = 1-6 / 7-18 / 19-36



and, missiles must accelerate from rest... if you do the math, what seems to work well w/ the above would be

SRMs gain +3MP of speed per hex of range
MRMs gain +2MP of speed per hex of range
LRMs gain +1MP of speed per hex of range

game effect: if some unit is moving faster than the missiles (e.g. Dasher dashes past, at point blank, from the firer of many missiles)...
then the missiles miss, b/c they cannot keep up with the target darting across the LOS...
all missiles reach / obtain speeds of 36MP before the motors cut out -- all missiles obtain 6MP in the last hex of their SR bracket, 18MP in MR, to 36MP in LR


in 3025, you might not be able to target a Locust, w/ LRMs, at <10 hexes range (unless the Locust was shut-down, or otherwise slow-moving or stationary)

in 3050, a sprinting MASC-ing Dasher could outrun nearly all missiles, in their Short & Medium range brackets