Why do Autocannon have a minimum range?

[Zombyra]

I mean, I know the game reason autocannons have a minimum range, I guess; balance the weapons--blah, blah, blah--long range has a penalty--blah, blah, blah.

But honestly, I'm more of a fan of the fluffy reasons for stuff, and I don't want to kill too many catgirls--because I do love them so--nevertheless I at least want to know the going excuse, if not an actual reason for this.

I understand PPC's i think--energy focus; something about feedback, whatever.  And LRM's--arcing missiles, yeah, ok.  But autocannons? All I can think of is sure it's got to be a long barrel on that gun--but it's not that long of a barrel, and it's not any worse off than the large lasers mounted out on the end of those massive arm-looking things.  But for some reason that guy 50 yards out is harder to hit than that guy that's 100 yards out--what? Also, there's alot of variance among the type of autocannon and the applicability of the extent of the minimum range--so my house rule is, AC's don't have a minimum, because it doesn't make any sense.  BUT, I'd still love to hear the explanation--real world, fluffed-out, or otherwise--and maybe I'd even relent a little--maybe.

[Nahuris]

Actually, there was a fluff entry about this that stated it was due to the weight of the AC, which made it difficult to do subtle aiming corrections.... but never bothered explaining then why the 14 ton AC/20 didn't have minimums, but that the 6 ton AC/2 did.....

I just consider it one of the quirks of battletech and just play the game...... although AC's without minimums would be interesting..... it would make a 3025 Blackjack, or Jagermech more interesting.

Nahuris

[George_Labour]

Perhaps it has to do with the issues of bringing a 'mere' super or hypersonic weapon onto the target, getting the targeting solution, pointing the boom stick the right way and firing the weapon in a mostly accurate manner while the firing unit is itself trying to not get shot.

This would especially hold true with (bipedal) mechs as their humanoid nature works against them in this instance.

If you don't stop to think about it to closely those are almost plausible enough to explain away the matter.

[cray]

They're not weapons meant for point-blank engagements. Barrels too long, aiming adjustments too slow, whatever - some guns and missiles don't do well at point blank range. Consider using a long rifle like an M1 Springfield in a close-quarters, indoor furball against folks with compact machine guns.

And there's the example of the USS Samuel B. Roberts, which actually got so close to much larger Japanese cruiser Chokai that cruiser couldn't shoot the Roberts.
http://en.wikipedia.org/wiki/Battle_off_Samar#USS_Samuel_B._Roberts

[monbvol]

Except that doesn't really work when the same actuators/turret drives have no trouble moving around bigger and heavier weaponry without applying minimum range penalties and Battletech is certainly capable of a much better field of fire than the Chokai which had that particular problem more because of turret and mounting design than the guns themselves.

Fusing problems from too high of a muzzle velocity doesn't make sense either because some ACs are using pure kinetic impactors and those don't keep getting faster after they leave the barrel.

So yeah I too eliminate the minimum ranges on top of all the other things I do for ACs.  Yes I include Gauss Rifles in that but to balance those out I cause them to generate a lot more heat and behave like Plasma Rifles on vehicles(needing power amps if ICE and needing heat sinks).

Everything else is easier to understand from their fluff explanations even if I think the game mechanics go about it in the wrong way sometimes.  PPCs I can understand the field inhibitor causing a delay in the charge build up of the PPC causing a delay between trigger pull and firing that causes accuracy issues close in so that one is fine as is.  LRMs from what I remember are due to the fuses not always arming before hitting the target because they fly so fast.  Reasonable enough explenation but poor execution there.  It'd be easier to go with that if it were a penalty to the cluster hit chart rather than a penalty to hit.

[Lord Cameron]

I mean, I know the game reason autocannons have a minimum range, I guess; balance the weapons--blah, blah, blah--long range has a penalty--blah, blah, blah.

But honestly, I'm more of a fan of the fluffy reasons for stuff, and I don't want to kill too many catgirls--because I do love them so--nevertheless I at least want to know the going excuse, if not an actual reason for this.
sense.  BUT, I'd still love to hear the explanation--real world, fluffed-out, or otherwise--and maybe I'd even relent a little--maybe.

Think about a 100 or 120 mm gun, it can target tanks or inf at some distance out.
But try to hit a moving target at 20 or 30 feet away? Not so easy.

A target moving the same speed but at a much closer distance has a much greater relative movement as seen from the shooter

[beachhead1985]

so my house rule is, AC's don't have a minimum, because it doesn't make any sense.  BUT, I'd still love to hear the explanation

that is a very common house rule in my experience

[Nikas_Zekeval]

I believe one of the early novels fluffed it as longer range ACs had long barrels for accuracy, and couldn't turn them as fast in close engagements.  The AC/10 and AC/20 were relatively shorter barrels, and thus handier to turn.

[I am Belch II]

Because some weapons just have issues. Like the parachute on the Heavy Gauss Rifle!!!

[SCC]

The guns are set/designed for long range engagement, you can't change that in a 'Mech on-the-fly, CV's in theroy

[Jellico]

Except that doesn't really work when the same actuators/turret drives have no trouble moving around bigger and heavier weaponry without applying minimum range penalties and Battletech is certainly capable of a much better field of fire than the Chokai which had that particular problem more because of turret and mounting design than the guns themselves.

Fusing problems from too high of a muzzle velocity doesn't make sense either because some ACs are using pure kinetic impactors and those don't keep getting faster after they leave the barrel.

So yeah I too eliminate the minimum ranges on top of all the other things I do for ACs.  Yes I include Gauss Rifles in that but to balance those out I cause them to generate a lot more heat and behave like Plasma Rifles on vehicles(needing power amps if ICE and needing heat sinks).

Everything else is easier to understand from their fluff explanations even if I think the game mechanics go about it in the wrong way sometimes.  PPCs I can understand the field inhibitor causing a delay in the charge build up of the PPC causing a delay between trigger pull and firing that causes accuracy issues close in so that one is fine as is.  LRMs from what I remember are due to the fuses not always arming before hitting the target because they fly so fast.  Reasonable enough explenation but poor execution there.  It'd be easier to go with that if it were a penalty to the cluster hit chart rather than a penalty to hit.

Weight is part of the equation but also shape.
If you have ever watched Olympic Archery you will notice the strange long pieces of metal in front of the bows. They are basically weights. By putting the weight at the end of a long stick they increase the amount of force needed to rotate the bow around the pivot that is the archer's wrist. This effectively stabilises the bow. The longer the sticks the lighter the weights need to be.

Same applies with rifles. A rifle intended for long range shooting will often have a heavier barrel. Especially if the shooter doesn't have to carry it on foot much.

Now as has been noted above, if light autocannon have long barrels and heavy autocannon have short barrels the 'Mechs actuators could well require more effort to rotate the lighter weapons.

[A. Lurker]

Anime physics -- the same reason smaller-caliber ACs have a longer range than their bigger cousins in the first place.

If you look at an AC/2, it probably has a fairly long barrel relative to its tiny caliber (if it was too short, it would magically lose five and a half tons of weight and turn into a machine gun :) ). Thus, it looks as though it should be shooting farther and be harder to maneuver than the relatively short-and-stumpy AC/20...and thus, in BattleTech, it does.

[monbvol]

I get the principle but as I said before Battletech obviously has actuators capable of moving more weight and longer barrels than an AC-2 without generating a minimum range for it.

[cray]

Except that doesn't really work when the same actuators/turret drives have no trouble moving around bigger and heavier weaponry

I don't agree with that argument. Weapons are not built with the best of everything for every situation. Designers often make compromises to help weapons excel in one area at the expense of others.

Yes, awesome, some large BT weapons aim quickly and easily at point blank ranges because they were designed to do so. That doesn't mean the same actuators were carried over to longer-ranged ACs. The longer-ranged ACs were optimized for longer ranges, with associated compromises in point-blank performance. Be it their targeting, actuators, long barrels, or something else, they were compromised to excel at longer-ranged combat. Sticking with the Chokai...

without applying minimum range penalties and Battletech is certainly capable of a much better field of fire than the Chokai which had that particular problem more because of turret and mounting design than the guns themselves.

...By your own logic that shouldn't happen to the Chokai because there are other proven, centuries-old mountings for cannons that allow ships to rake the waterline. Because of such guns, clearly the Chokai should've been able to shoot any ship at any angle along side it. If we're to follow your logic, the Chokai has no excuse for being unable to shoot the Robertson. Its cannons should've been on the old, proven pintle mounts with excellent arcs of fire.

But those mountings have problems of their own, don't they?

I get the principle but as I said before Battletech obviously has actuators capable of moving more weight and longer barrels than an AC-2 without generating a minimum range for it.

At the expense of long-ranged performance. The actuators ABLE to move AC/20s rapidly to target short-ranged threats are clearly unsuited for aiming at long-ranged threats. Look at the poor long-ranged performance of the AC/20.

[monbvol]

And yet an Arrow IV in direct fire mode has no minimum range and that is certainly a more unwieldy weapon in close.  Sure you have to put it in a turret but the even bigger Long Tom has no trouble firing in close.  Even if we discount those because they operate differently than standard ACs I'm still not entirely sold on the idea since the same mountings have considerably little trouble tracking an ASF at high altitude moving at several times the speed of sound or swinging 3 AC-2s a minimum of 180 degrees in less than 10 seconds.

Like I said I understand the principle.  It is just how everything else meshes and the implications they create in the process.

[A. Lurker]

And yet an Arrow IV in direct fire mode has no minimum range and that is certainly a more unwieldy weapon in close.  Sure you have to put it in a turret but the even bigger Long Tom has no trouble firing in close.

Barring a pointblank shot from a hidden artillery unit (i.e., basically the target stepping right in front of your barrel), you can't make a direct-fire artillery attack against anything within six hexes at all (TacOps p. 185).

[Zombyra]

I think this has been a great discussion to this point, so I wanted to thank everyone for putting in  :-*

When I saw this:

I get the principle but as I said before Battletech obviously has actuators capable of moving more weight and longer barrels than an AC-2 without generating a minimum range for it.

I thought about coming back with the question: Everything gets mounted in the same places; why don't erLL and erPPC's have a minimum range then?  They're big and heavy and shoot a long way, even farther than the autocannon, honestly.  I almost came back with that question.  But then I remembered somebody said this:

Anime physics

A. Lurker, you've got to be some kind of a genius, really. 

In Anime, laser guns kick back, don't they?  Usually with a big circle of ambient energy, possibly pushing back your giant robot and creating a corridor of dust stirred up by the energy wave  :)) 

And because already somebody had said this:

And there's the example of the USS Samuel B. Roberts, which actually got so close to much larger Japanese cruiser Chokai that cruiser couldn't shoot the Roberts.

(I'm familiar with the engagement, an old hobby of mine)
and this:

If you have ever watched Olympic Archery you will notice the strange long pieces of metal in front of the bows. They are basically weights. By putting the weight at the end of a long stick they increase the amount of force needed to rotate the bow around the pivot that is the archer's wrist. This effectively stabilises the bow. The longer the sticks the lighter the weights need to be.

(but I've never even seen olympic archery)

I started to fear for my catgirls.  Because while I want to think about a real world explanation, I still dearly love my catgirls.  And because I love them, I must acknowledge that this . . .

I get the principle but as I said before Battletech obviously has actuators capable of moving more weight and longer barrels than an AC-2 without generating a minimum range for it.

. . . is still essentially correct.  Size and motion and weight really get swallowed up by the whole--giant-stompy-robot-warrior lover in me.  Except at literally-kicking-you-in-the-face-point-blank-range, I don't think the size of the barrel really matters in that it's not the principal cause of the problem.  And I don't think it's relative motion.  If that were true every weapon mounted on a mech would have the same problem with sweeping their weapons in close quarters.  If it's just the aiming, a closer target is also a relatively bigger target, and the speed of target is already kind of swallowed up by the to-hit-mod.  It's not that they're bad explanations or something like that--I've heard some of them before--but it's unsatisfying somehow.  I know: tough cookies, eh?

Nevertheless all this prompting got me to thinking a little more closely about precisely what exactly an autocannon really is.  Isn't is really more like an automatic or assault rifle? (I mean as opposed to the rotary style cannon on an A-10 Warthog)  I seem to remember from the fluff somewhere: variable calibers, variable number of rounds.  That AC5 might be putting out 10 rounds--which because they aren't calculated as discreet units--deal 5 damage.  The AC20 might be putting out 10 rounds or 50 rounds depending on the caliber of the weapon; it just deals 20 damage when you hit.

Lasers really don't kick back.  But an automatic rifle has a problem I can relate to--climb.  When you fire in auto-mode the weapon trys to travel on you--simply put, and for the purposes of my explanation, it has a kick which makes the next round inaccurate--unless you compensate by pulling the weapon down.  There are even assault rifles that are designed to fight climb or have design features to make the weapon climb neutral in auto mode.  And if that's how autocannon are modeled, I think I might have a good explanation.  (With thanks again to everyone)

Someone what knows something about ballistics should probably stop me, but see if I've got some good fluff here:

When you fire an autocannon, you let lose with a 'round' that is essentially a preselected clip of several large caliber, high energy projectiles that go pouring out of a barrel, really fast. The pressures and energies are huge, even for a giant fusion powered robot to handle; the necessity that internal to the cannon are auto-stabilizers designed to fight the 'kick' generated by each round as it leaves the barrel.

The internal stabilizers are designed to account for the battlemech in motion--and against the kick of the magazine of whatever caliber--no matter the number of rounds.  Heavier autocannons are designed with higher grade and much heavier stabilizers, since these weapons are designed for close quarters fighting.  Lighter autocannon are designed for finer adjustments at longer ranges; their internal stabilizers aren't designed to compensate for the faster momentum changes required to follow a target during firing in close range combat.

It's not an aiming problem--it's a during-the-firing-of-this-weapon problem, like the lrm's and ppc's.  It's kind of fluffy too, that's why I like it.  Today at least, this seems to me like a pretty satisfying explanation as it also makes some sense out of a quirky little issue: how come an lbx or ultra 10 which fires at the same range as an ac5, the 10 doesn't have a min?  And while you 'could' theoretically design an AC2 with heavier stabilizers for close range combat, for whatever reason the battletech universe doesn't demand them.  The four sizes of autocannon represent a range of calibers and designs that are fluffed out to be the optimal mix of caliber, range, and weight; it's what manufacturers design around, and it's what customers want--for whatever reason.

Of course I'd be shocked to find out this is a good answer; I'd still like to encourage more brainstorming!
 [watch]

[Blackjack Jones]

Well Zombyra, keep in mind that lasers and heat weapons are the only two "families" of ranged weapons that don't have a black sheep with minimum range in them.
The problems with tracking/recoil/minimum safe distance/etc. extend to ballistics, missiles, and PPC's in various capacities.

As for lasers themselves, there's a pretty good argument to say any "barrel" past the focusing lenses is just there in a protective (or aesthetic) capacity, so they aren't as heavy
or unwieldy as a barrel of a ballistic weapon. And with the proper focusing/aiming gear, a laser's target doesn't necessarily need to be on the centerline of the complete weapon assembly,
as you don't need to maneuver the power generation gear, just the focusing assembly and lenses. A ballistic weapon needs to line up everything from the breech to the end of the barrel.
This can translate to needing much less time to get a bead on the target for a laser. Or to put it another way: An AC/2 might be trying to aim almost all of it's six tons at a target,
where a Large Laser might only be aiming a ton or two.

For reference see:

http://en.wikipedia.org/wiki/Airborne_Laser
http://en.wikipedia.org/wiki/Advanced_tactical_laser
 
And let's have a look at Gauss weapons for a minute: except for Magshots and APGRs, every vehicular class Gauss weapon has a minimum range of some kind.
We know Gauss weapons are more efficient than AC's from a power to weight ratio, so even if they didn't have tracking problems, recoil is apparently still a problem.

[Nikas_Zekeval]

I get the principle but as I said before Battletech obviously has actuators capable of moving more weight and longer barrels than an AC-2 without generating a minimum range for it.

It's not just mass, but how it is distributed.  Everything has a moment of inertia, which represents how hard it is to turn, or to stop turning once you start it.

For swinging a rod by it's end (simplified model for a cannon barrel) the formula is I=(mL^2)/3  Or one third the mass times the square of the length.  So the force needed to affect it's rotation is half if you cut the mass in half, but quadrupled if you double the barrel length.  Or doing both and you get something that has twice the moment of inertia.

[cray]

And yet an Arrow IV in direct fire mode has no minimum range and that is certainly a more unwieldy weapon in close.

Alright, monbvol, then please explain the minimum range of BT's ACs. It's easy to sit back and reject any alternative that works but has a contradiction in unrelated weaponry, but why don't you try working from the other side and build up a plausible explanation that fits the rules?

[HavocTheWarDog]

Having served in the artillery thats more of an elevation problem than a targeting problem!

[chanman]

Alright, monbvol, then please explain the minimum range of BT's ACs. It's easy to sit back and reject any alternative that works but has a contradiction in unrelated weaponry, but why don't you try working from the other side and build up a plausible explanation that fits the rules?

AC/2s are actually gyroslug weapons, explaining their low explosive payload, relatively low weapon weight, and ludicrous range. They are simply difficult to use at close range because the propellant is relatively anemic and the booster motor hasn't yet accelerated the projectiles to cruising speed yet.  O:-)

[monbvol]

Alright, monbvol, then please explain the minimum range of BT's ACs. It's easy to sit back and reject any alternative that works but has a contradiction in unrelated weaponry, but why don't you try working from the other side and build up a plausible explanation that fits the rules?

Simple.  I can't explain why they do have a minimum range in a satisfactory way without creating contradictions as to why other equipment doesn't or why different mounting locations don't impact the minimum range.  After all it stands to reason that a Torso mounted AC should have even more difficulty tracking a target in close due to a more confined mounting but it doesn't.  Likewise I can't explain why the minimum range on the AC-2 Carrier's Front mounted AC-2s isn't longer than the Turret mounted AC-2s of the Pike Support Vehicle.

Sometimes something happens in the rules that probably shouldn't.  Fluff tries it's best and sometimes it does offer plausible explanations.  After all Battletech is not a reality simulator but there are some people who certainly know their stuff writing for it.

If Battletech were a better reality simulator oh yeah no problem.  The reasoning is sound.  I do understand it and I do not refute that targets in close are a bit more of a problem for long barreled weapons with our current understanding of mounting techniques and technology.  My problem does stem from Battletech repeatedly demonstrates that it has superior mounting techniques and technology though.

Maybe I am just too hung up on it being a game though.

[stoicfaux]

Ugh, barrel length as the reason?  Really?  That may work for the Shadowhawk or Rifleman, but not for the Wolverine or the Daikyu, and the latter has AC/5s embedded in its forearm, the barrels of which don't extend far enough to even interfere with the hand actuators and thus should be easy to maneuver at point blank range.  The Daikyu's AC5s really are point and click.

Plus, even with the long barrels of the Shadowhawk and Rifleman, any target that's two or more hexes away is definitely not close enough for barrel length to matter anymore, so the long rifle in close quarters battle excuse doesn't hold water either.


Which leaves either ammo or tracking as the culprit(s).

[monbvol]

Ugh, barrel length as the reason?  Really?  That may work for the Shadowhawk or Rifleman, but not for the Wolverine or the Daikyu, and the latter has AC/5s embedded in its forearm, the barrels of which don't extend far enough to even interfere with the hand actuators and thus should be easy to maneuver at point blank range.  The Daikyu's AC5s really are point and click.

Plus, even with the long barrels of the Shadowhawk and Rifleman, any target that's two or more hexes away is definitely not close enough for barrel length to matter anymore, so the long rifle in close quarters battle excuse doesn't hold water either.


Which leaves either ammo or tracking as the culprit(s).

Actually the Rifleman is a great example of why barrel length as the reason why ACs have a minimum range creates a logical disconnect.

Look at the original art work for the base model Rifleman.  Even if we accept that there is independent rotation on the horizontal axis the mounting clearly shows that both weapons on the arm are using the same actuator for vertical rotation.  Even if that assumption is wrong looking at it the mounting clearly is not suited for more than a few degrees of independent vertical rotation which is fine against targets farther away.  So obviously against close targets at different elevations the arm mounted lasers obviously have to contend with the weight of the barrel of the AC and yet they don't have a minimum range in this case.

[BirdofPrey]

Because it's a game and things get done for balance reasons even if they don't make sense.
Also the fluff is much less abstract.  The game would be far too complicated if every mech had a completely unique method of operation.

[chanman]

Gyroslugs. The long period of time they spend accelerating in the barrel means that longer barrels are more adversely affected by sudden movement.

[monbvol]

Autocannons have enough going against them that they really don't need a minimum range on top of everything else.

Rocket assisted makes the most sense so far but I have memories of AC-5s using unassisted kinetic impactors and unassisted shaped charge shells.  I can't really think of any fiction I've read where AC-2s have even come up, let alone what kind of ordinance they use.

[MoneyLovinOgre4Hire]

The only time I can remember AC-2s coming up in one of the novels was in Binding Force when Ares got into a fight with a BJ-1 Blackjack, but the minimum range was never mentioned.

[Nebfer]

Per the fluff Autocannons fire Depleted Uranium tipped High Explosive Armor Piercing ammo.

The easiest way to explain minimum range is likely that it's a mix of reasons. Targeting and tracking may be at fault for some, others it might be weapons configuration, and other ammo types used.

Some ammo types have fuzes that require it to spin so many times before it arms it self, others require elements to fall away before it's main component will work effectively (like a sabot). Some weapons may be configured to hit targets accurately out to a much longer range than others and as such they may have some difficulty hitting targets up close.

[RedDevilCG]

I always thought of it as the mount on the arm has a fine motor-screw to adjust for long distance fire.  Sort of like 20 revolutions of the screw adjusts about 1 degree of elevation or side to side.  The weapon isn't actually aimed by the arm, or by bending the torso backwards and forwards; it is just mounted there.

Heavier weapons meant for close range, have courser motor-screws that adjust rapidly; like 1 revolution adjusts for 1 degree, but these same motors don't have fine enough control for tiny adjustments needed for extreme range fire.

For long range weapons, when a target gets in closer, the pilot can no longer rely on the weapons built in auto-targetting range of motion, as the motor is to slow to track, but now has to swing the arm around, or tilt his torso in awkward ways to track his target, so it gets harder to hit.

Imagine that you had a gun attached to your chest, and you had to fire it at 60m against a target moving 55km/h, just by bending and twisting at the hips stiff-robot style ;D



Lasers don't suffer as much from this, as they don't fire shells affected by gravity, and don't have to lead the target as much.  I dunno.  And BTW I think the IS PPCs do have a minimum range.

[willydstyle]

It's not just mass, but how it is distributed.  Everything has a moment of inertia, which represents how hard it is to turn, or to stop turning once you start it.

For swinging a rod by it's end (simplified model for a cannon barrel) the formula is I=(mL^2)/3  Or one third the mass times the square of the length.  So the force needed to affect it's rotation is half if you cut the mass in half, but quadrupled if you double the barrel length.  Or doing both and you get something that has twice the moment of inertia.

This is entirely correct, and is an excellent reason why barrel length could well be a factor, even on a mech such as the WVR that has a "rifle mount" for it's AC.

[SCC]

maybe the on-mount sensor suck, I mean cybernetics in BT tend towards to lower end

[MoneyLovinOgre4Hire]

This is entirely correct, and is an excellent reason why barrel length could well be a factor, even on a mech such as the WVR that has a "rifle mount" for it's AC.

And this, of course, becomes a problem when it comes to mechs with short barreled ACs in their torsos, like the Mauler.

I blame BT's inconsistant artwork.

[Blacksheep]

Because BT physics were built around developing a beer & pretzels game...probably heavier on the beer side.  In reality, the heavier the gun the more a minimum range makes sense, but alas, not in BT.  Similarly, for another example, heavy machine guns have a shorter range (if that was even possible for an MG in BT)...again, no basis in reality.  Frankly, IMHO, there is no reason for this and many of us have expressed these gripes repeatedly over the years.  You just have to let it go.

[Tree]

Because BT physics were built around developing a beer & pretzels game...probably heavier on the beer side.  In reality, the heavier the gun the more a minimum range makes sense, but alas, not in BT.  Similarly, for another example, heavy machine guns have a shorter range (if that was even possible for an MG in BT)...again, no basis in reality.  Frankly, IMHO, there is no reason for this and many of us have expressed these gripes repeatedly over the years.  You just have to let it go.

I have to agree with Blacksheep.  I and others I have played with, have debated these things for many years.  Until the "Head Honchos" decide to change the rules... ain't gonna happen, "Game" balance and all that.   That's why there are all those nifty "house rules".  O0

[Wildonion]

I always thought of it as the mount on the arm has a fine motor-screw to adjust for long distance fire.  Sort of like 20 revolutions of the screw adjusts about 1 degree of elevation or side to side.  The weapon isn't actually aimed by the arm, or by bending the torso backwards and forwards; it is just mounted there.

Heavier weapons meant for close range, have courser motor-screws that adjust rapidly; like 1 revolution adjusts for 1 degree, but these same motors don't have fine enough control for tiny adjustments needed for extreme range fire.

For long range weapons, when a target gets in closer, the pilot can no longer rely on the weapons built in auto-targetting range of motion, as the motor is to slow to track, but now has to swing the arm around, or tilt his torso in awkward ways to track his target, so it gets harder to hit.

Imagine that you had a gun attached to your chest, and you had to fire it at 60m against a target moving 55km/h, just by bending and twisting at the hips stiff-robot style ;D

Lasers don't suffer as much from this, as they don't fire shells affected by gravity, and don't have to lead the target as much.  I dunno.  And BTW I think the IS PPCs do have a minimum range.

Oh, I like that explanation! +1

[majesticmoose]

Oh, I like that explanation! +1

Plus, now with light AC's and HV AC's you get the other side of that, where large caliber AC's have longer ranges w/minimums, and smaller calibers that have shorter ranges and less or no minimums.

The system is now very contextual, since there are large numbers of AC's to compare to. 

Still, I'd jsut say it has to do with the mounting and designed operational range.

[Lonesome Crow]

I like Intro tech in part for minimum ranges because it strikes me as more interesting, so Rule of Cool reduces my need for reasonable expanation, but for what it's worth...

The main fluff problem I've had with autocannon is the weird relationship between mass, power and range.  I like absurdism, so I picture the AC/5 and AC/2 weighing so much for their performance because they're equipped with massive flywheels to stabilise them. :D  AC/20 are easier to aim despite being much more massive because you don't have to fight a gyro, and also because only part of that mass has to be aimed anyway- like lasers vs. PPC.  (Lighter AC can't split crits, but a class 20 can.) 

[Wrayth]

The more I think about the barrel length arument, the more weight I think it holds.  It also explains something that had always bothered me: the severely limited range of AC20's.  Basically, let's assume the long barrels on AC2's and AC5's really do make them unwieldy and hard to track targets up close with.  That allows us to make that supposition that the limiting factor on the range of AC10's and AC20's is the length of the barrel; in effect, the AC20 has a short or snub-nosed barrel which limits its effective range.  This short barrel also explains why they don't get the minimum range penalty; they're like the carbine version of real life rifles.  You see the same thing with the "light" versions of the AC5 and AC2 - reduced range and the removal of the minimum range penalty.

To me, this all seems to hang together quite nicely, but it begs the question: why didn't they just build a longer barrel onto the AC20 to allow it to hit further out?  Simple: weight.  At 14 tons, the short-barrelled AC20 is already beastly and hard to cram into a mech, and adding a longer barrel would add significant weight and crit space, making it that much harder to fit.  As a result, any further weight would make it impractical (if not impossible) to mount them on any mobile platform short of a dropship.

In any case, given how well this all seems to fit together, the "longer barrels are unwieldy" explanation now makes perfect sense to me.

[stoicfaux]

In any case, given how well this all seems to fit together, the "longer barrels are unwieldy" explanation now makes perfect sense to me.

Looks at Wrayth.  Looks at the Hermes II HER-2S.  How exactly does that long barrel theory apply to the Hermes' torso mounted autocannon...?

[willydstyle]

The way most mechs are drawn, torso mounted weapons look like they don't really have any sort of aiming mechanisms at all.

[MoneyLovinOgre4Hire]

Sure they do- the mech's waist.

[RedDevilCG]

Yeah, barrel length is all over the place.  I still like the explanation of trade-offs:

-That light ACs track very slowly, but very precisely to hit far targets. 
-Heavy ACs track very quickly (to smash NOW anything that gets too close), but not very precisely so can't hit far targets.

[Blacksheep]

In that case, I will take my AC sight tuning spork and adjust my AC/20 to fire in the AC/5 range bracket accepting that modest three hex minimum range penalty O0  Works for me ;)

[RedDevilCG]

Sounds good to me too!  Super Gauss!

[SCC]

Pity you can't just fit it with 2 turning mechanism for no min range

[stoicfaux]

Sure they do- the mech's waist.

Jenner.  Hoplite.  War Dog.  Mechs that don't have waists.   :P

[willydstyle]

Not to mention that a mech's waist doesn't seem like it can rotate fast enough to track a moving target.

[MoneyLovinOgre4Hire]

That's why mechs have hips, knees, and ankles. :P

[Nahuris]

Actually, what I've always wondered most about AC's is this..... why can I walk my AC fire across 2 hexes, but I can't walk it across 2 torso locations?

Nahuris

[monbvol]

The game rules certainly do seem to contradict the fluff that ACs fire bursts up until that splitting fire rule.

[Lafeel]

Wouldn't it also be possible that certain ac rounds, just like certain missiles, need the time, and therefore distance, to arm?

[stoicfaux]

Wouldn't it also be possible that certain ac rounds, just like certain missiles, need the time, and therefore distance, to arm?

Because AC rounds have been described as using "kinetic penetrators" don't have arming mechanisms. 

There's also the small problem that autocannons that use the same ammo have differing minimum ranges.  Ex:  AC-5 - three hex minimum range versus the Ultra-5's two hex minimum range yet both use the same ammo.  The RAC-2 has no minimum range yet all other AC/2 class weapons use the same ammo.

[A. Lurker]

There's also the small problem that autocannons that use the same ammo have differing minimum ranges.  Ex:  AC-5 - three hex minimum range versus the Ultra-5's two hex minimum range yet both use the same ammo.  The RAC-2 has no minimum range yet all other AC/2 class weapons use the same ammo.

Actually, ammo for different autocannons is different even if they're notionally of the same "class" (i.e., have the same damage value). AC/5, UAC/5 and RAC/5 shells are not interchangeable.

And while I'm at it, as per TechManual fluff "most autocannons deliver their damage by firing high-speed streams of high-explosive, armor-defeating shells through one or more barrels" (p. 207, "Autocannon" intro section, emphasis mine). No mention of kinetic penetrators being the default -- in fact, wouldn't that be more the particular hat of Gauss weaponry?

[MoneyLovinOgre4Hire]

It depended on who was writing the description.  But AC rounds were typically described as being explosive.

Also, Light ACs use the same ammo as standard ACs of the same size.

[A. Lurker]

Also, Light ACs use the same ammo as standard ACs of the same size.

I'm actually not so convinced. Sure, light ACs get the same selection of special ammo types as standard autocannons, and a ton costs the same number of C-bills...but the table on TM p. 345 still gives the "standard" ammo types for each different Tech Ratings (C for standard, D for light), suggesting that they actually are distinct. I mean, if LACs simply chambered standard AC rounds, surely Tech Rating C would apply to both?

[MoneyLovinOgre4Hire]

No idea.

[Daemion]

Actually, what I've always wondered most about AC's is this..... why can I walk my AC fire across 2 hexes, but I can't walk it across 2 torso locations?

Nahuris

I actually think this has a lot to do with this:

The game rules certainly do seem to contradict the fluff that ACs fire bursts up until that splitting fire rule.

Don't forget the ranges that these same weapons get when tacked onto an Aerospace craft, and the flight times which suggest "Ludicrous Speed!!!" as the velocity at which they travel.

Projectiles in BT, in order to get the kilometers space ranges in the 10 or less (most obviously less) seconds one can expect it to fire and still hit the target on time, are moving at insane speeds that modern ballistic engineers only dream about.

BT Missiles aren't armed while in the tubes. They arm themselves in flight. I imagine that inside the first 6 hexes, they've only been in the air the smallest fraction of a second.

How does this apply to ACs? Have you notice how they group their damage? It's all or nothing with an AC. At least with Missiles, you get partial cluster sizes. With ACs, it's full damage for a group, or it's a miss.

While I'm one to laud the accuracies inherent in a futuristic weapon tied to a futuristic targeting system, ACs do have the high recoil to deal with. The larger class ACs have massive recoil to handle for the shear power they're pumping out inside a second or two. It's all they can do to keep the AC on a large target, let alone expect it to have all its shells slam home on a specific area on that target.

I'm one that follows the idea that if you don't group the shells or the shot well enough, the armor, or the defensive stance of the Mech combined with the armor, deflects the shots 'harmlessly'. If you spread your shots across multiple locations, you just got a miss. In game terms you don't get to roll for location and color in armor or internal structure boxes.

If the AC, and the Mech itself, are fighting the recoil of the weapon, then it seems like a true hit is next to impossible. But, it happens with some regularity. Why? Because I think there's more to the ammunition ACs use than is told to us.

I posit that BT ballistic munitions are smart rounds, that home in on a designated target via controlled spin or fin stabilization, or whatever. If a weapon groups its shots well enough, they'll all home in and do the damage, otherwise, they spread out too far and do nothing more than 'scratch and burn the paint'.

The lighter Autocannon classes are dealing with the same recoil. Sure, they're not trying for massive groupings, but they are trying for range, and to get that range, the rounds have to pour out the barrel at a greater velocity. Some limitations could also  be attributed to the size of the rounds, as well. But, that extra fraction of a second is all that is needed to keep the spread from homing in successfully.

The longer I play, the more I try to mentally visualize what's actually happening, the more I come to believe it's not any one thing that allows for a certain aspect to happen. It usually ends up being a combination of factors which may or may not overlap with other game aspects.

[Stolenbjorn]

Nice thread, I love AC-discussions. I have nothing of value to add, I allways pretended AC's were more like auto firing recoilless rifles, where the ac/20 was more like a short range-thick HEAT-warhead, whereas the ac/2 and 5 were thinner calibered HEAT-warheads with rockets that fired making the warhead rotate, and the rotation was slow and inaccurate at close range.

I allways wondered why AC's were treated so poorly in basic battletech. It seems to me (after playing some hours of megamek), that ammo really isn't worth the effort, and that there's no reason to mount AC\s (missiles do have something for them, so the risk of ammo explotion is somewhat mended).

I once made a marauder with 2 x ac10's and one large laser in the center torso, too bad it would never work in combat, i love the look and thought of shell-casings dancing to the ground   :-\

So I resort to houserules as well; I let AC-slugs penentrate, and have bigger chanse of crits; that outweighs all the things they're having against themselves  :D

Only sad thing is that I love MegaMek, and I don't bother trying to work my houserules into the system, don't know enough computer-stuff to do that. But I do try to put all optional rules into laser-hate-mode, and mark on anything that improves ac's  :)

[Nebfer]

I actually think this has a lot to do with this:

Don't forget the ranges that these same weapons get when tacked onto an Aerospace craft, and the flight times which suggest "Ludicrous Speed!!!" as the velocity at which they travel.

Projectiles in BT, in order to get the kilometers space ranges in the 10 or less (most obviously less) seconds one can expect it to fire and still hit the target on time, are moving at insane speeds that modern ballistic engineers only dream about.

BT Missiles aren't armed while in the tubes. They arm themselves in flight. I imagine that inside the first 6 hexes, they've only been in the air the smallest fraction of a second.

How does this apply to ACs? Have you notice how they group their damage? It's all or nothing with an AC. At least with Missiles, you get partial cluster sizes. With ACs, it's full damage for a group, or it's a miss.

While I'm one to laud the accuracies inherent in a futuristic weapon tied to a futuristic targeting system, ACs do have the high recoil to deal with. The larger class ACs have massive recoil to handle for the shear power they're pumping out inside a second or two. It's all they can do to keep the AC on a large target, let alone expect it to have all its shells slam home on a specific area on that target.

I'm one that follows the idea that if you don't group the shells or the shot well enough, the armor, or the defensive stance of the Mech combined with the armor, deflects the shots 'harmlessly'. If you spread your shots across multiple locations, you just got a miss. In game terms you don't get to roll for location and color in armor or internal structure boxes.

If the AC, and the Mech itself, are fighting the recoil of the weapon, then it seems like a true hit is next to impossible. But, it happens with some regularity. Why? Because I think there's more to the ammunition ACs use than is told to us.

I posit that BT ballistic munitions are smart rounds, that home in on a designated target via controlled spin or fin stabilization, or whatever. If a weapon groups its shots well enough, they'll all home in and do the damage, otherwise, they spread out too far and do nothing more than 'scratch and burn the paint'.

The lighter Autocannon classes are dealing with the same recoil. Sure, they're not trying for massive groupings, but they are trying for range, and to get that range, the rounds have to pour out the barrel at a greater velocity. Some limitations could also  be attributed to the size of the rounds, as well. But, that extra fraction of a second is all that is needed to keep the spread from homing in successfully.

The longer I play, the more I try to mentally visualize what's actually happening, the more I come to believe it's not any one thing that allows for a certain aspect to happen. It usually ends up being a combination of factors which may or may not overlap with other game aspects.

Well to me LBXs firing Cluster seem to be using large scale AHEAD rounds, basically advanced proximity fuzed rounds, smiler to the Airburst ammo used by the XM-25 (speaking of which IIRC the AFFS also has this for rifle & shotgun ammo in the RPG).

Assuming B-tech autocannons are flinging rounds at very high speeds, one way to improve velocity is to deal with a light weight shell fitted with a shoe to fit to the barrel, Sabot rounds (I.e. APDSFS rounds) which dose not need to be only used on kinetic rounds HEAT rounds also use it (I.e. M830A1). Though Autocannon projectiles are an odd item, their fluffed as being HEAP, but they also are often mentioned as having DU tips, the closest rounds I can find that would seem to be what B-tech uses is the Mk 211 Raufoss (listed as HEIAP -High Explosive Incendiary Armor Piercing).

One technically dose not even need to go into capital scale to see evidence of high speed projectiles.
AA shooting can show this.

B-tech ASFs can be traveling at a velocity of 12, or 2,160kph (mach ~1.8), now I never heard of a good anti aircraft gun that fired shells that traveled at velocity's slower than the intended targets, and most successful guns seem to fire shells that are easily three to six times faster than their intended targets (I.e. the Flak 18 fired rounds at ~800m/s it's targets often flew under 200m/s), this is still largely true today, most real world AA guns still fire rounds in the 1,000m/s range but the "targets" still often fly under 300m/s. As B-tech Autocannons are considered some what effective in this role, it would seem to be that the rounds they fire are noticeably faster than their targets.

[innersphere3050]

There is no good reason for minimum ranges on autocannons....or any other direct fire weapon.  Arming of LRM warheads is the only one that makes sense.  We have always played with no minimum ranges for direct fire weapons.  This helps the AC/5 in a 3025 game.

But nothing can help the horrible AC/2

[willydstyle]

Of course no minimum on direct fire weapons also helps the PPC, which really doesn't need the help.

[MoneyLovinOgre4Hire]

Or Gauss Rifles, which really don't need the help.

[chanman]

Or Gauss Rifles, which really don't need the help.

Or HGR which *do*

[MoneyLovinOgre4Hire]

Really?  I've never found that to be the case.

[Nightlord01]

The only reason I could think of not yet mentioned is part of tech base. During the SW, the houses lost a lot of technology, including most of the extant weapons technology. Most components were produced at a few massive factories, all of which ran by automation, and when they broke, no one knew how to fix them.

Given that the Star League were the masters of standards, wouldn't it be pretty safe to assume that everything was made to a standard pattern? Even if there were multiple manufacturers, they may have all made their weapons to the same standard, with only layout or mounts being different.

Therefore, if all AC2s are made to a standard pattern, then they all have the same foibles, same with all AC20s. This would account for variation in more recent developments as well, as none of these were made from a standard pattern.

[ApokalypseTest]

While we are at it:

Why do heavier ACs have less range than lighter calibers?

Also: Why does the Heavy Gauss rifle have this loss of damage over distance but the normal Gauss doesn't? The heavier shells should have a better surface to volume ratio and fly further...

I find the tracking argument as feasible or unfeasible as any number of points in BT - why do people always start with ACs instead of the hundreds of other obviously unrealistic issues? Why the AC?

[Erkki]

Hello everyone. Some thoughts of mine:

LRM minimum range: warhead arming is the fluff explanation. A more probably/realistic reason is probably that like many RL missiles, the BT LRMs are actually 2-phase. First phase rapidly accelerates the missile to very high speed and the second(IRL usually also smokeless) phase keeps it at its speed. Finally the 2nd phase runs out and missile will burn Ek while maneuvering to target. Minimum range would be the range at which the 1st phase ends and the missile becomes most maneuverable.

AC minimum range: fluff explanation is the weapon turning/aiming. I dont think the shell(HE) explanation is valid: gyroscopic shell arming and self-destruction was used in the 1940s already, meaning the shell would get armed while it left the barrel by a 100% mechanical system using springs... Only explanation I can make up(that also explains the grouped or "slug" damage) is that the ACs too actually shoot some kind of self-propelled or semi-self propelled ammunition one at a time while barrels are still rifled and shells rotate to be more accurate.

On gauss: what if it doesn't shoot a Ek penetrator but a HE shell? It would explain the shell not losing its destructive power over range.

Of course there are still are more questions left... :)

[ApokalypseTest]

Point with Gauss is that it definitely uses a kinetic penetrator according to all fluff sources - and at this point the whole concept of the Heavy Gauss losing steam just breaks down (unless the regular one would too...)

[monbvol]

See problems no matter how you approach it.

The LRM issue is why I prefer minimum range penalizing the cluster hit chart instead of the to hit number.  It meshes better with any of the plausible explanations.

Gauss of any variety as have been pointed out fire kinetic penetrators.  No rocket assist.  Nothing that explains why they have a minimum range, or why it isn't worse than the AC's minimum range because that barrel has to be much heavier and longer than an AC-5's.  Nothing that explains why the Heavy loses damage so fast.

ACs, as pointed out fusing has had this problem worked out since the 40's and I do have solid memories of some ACs firing pure depleted uranium ammo, not some tipped HE hybrid.  I just can't remember which novel that was and thus what mech.  Barrel weight/length breaks down too.  All you have to do is look at the Jagermech's art from TRO-3025 or the Rifleman from original TRO-3025.  Their other arm mounted weapons clearly by the artwork share at least one axis of rotation if not both(vertical and horizontal).  So why don't the Rifleman's Large Lasers share the minimum range of the AC-5s on the same arm?  Or the Jagermech's AC-5's take on the AC-2's?

[Daemion]

Point with Gauss is that it definitely uses a kinetic penetrator according to all fluff sources - and at this point the whole concept of the Heavy Gauss losing steam just breaks down (unless the regular one would too...)

Actually, a lot of people point out that the ferrous nickel alloy that Gauss munitions are made of are not sturdy enough to do the job of a kinetic penetrator. If gauss munitions are fired at the speeds suggested by even the old AT1 space game, then it's most likely the gauss projectile is turned into a ball of highly reactive atoms, and vaporizes when it hits the target. Again, with the speeds involved, it's possible that the round isn't quite to that physical state while inside the minimum range of the gauss, and will just as likely shatter harmlessly as atomize the location struck.

Now, this might also explain the Heavy Gauss, too, as it loses a lot of its mass in its short flight duration, with loose atoms being stripped away by atmosphere or distance, depending on if you're on the ground or in space.

It's a suggestion, but obviously doesn't hold up when you bring in ground engagements in vacuum environments.

[Nebfer]

While we are at it:

Why do heavier ACs have less range than lighter calibers?

Also: Why does the Heavy Gauss rifle have this loss of damage over distance but the normal Gauss doesn't? The heavier shells should have a better surface to volume ratio and fly further...

I find the tracking argument as feasible or unfeasible as any number of points in BT - why do people always start with ACs instead of the hundreds of other obviously unrealistic issues? Why the AC?

Why the AC I would think it's likely one of the more obvious ones, and one of the few to have a some what analogous weapons system in real life.

Heavy Gauss I would think as an attempt to make it less powerful than it should be (25 damage at ~20 hexes, would make for a powerful weapon). And the fact that TPTB have a nasty habit of making the next generation of weapons more specialized and or have weird quirks, rather than out right better than the last generation. So explaining it would be impossible, I believe even in universe it was mentioned as puzzling. Though the novels have this strange habit of referencing Gauss Slugs as large Nickel-Iron cannon balls.

As for the range differences, Well like the minimum range theirs a few options, one is reduced propellent charge (and reduced MV) resulting in the Heavier guns having less range. Another is accuracy, under the assumption that in order to do damage requires autocannons to be quite accurate, And due to their having less recoil being produced than the heavier ones, lighter ACs have a longer effective range. Again it could be a mix of the two...

As for the tracking concept, theirs not one real good explanation for why ACs have a minimum range, it could be a mix of reasons, applied at different times on different mechs.

[MoneyLovinOgre4Hire]

What I'd personally like to see with regards to the HGR and iHGR is for them to be combined into one weapon some time in the future, using the damage of the iHGR with the mass of the HGR.

I'm doubtful that it will happen, but it would be nice.

[A. Lurker]

Why the AC?

Because people like the idea of having big loud honkin' guns on their war machines, yet in actual terms of game mechanics autocannons are generally considered to suck next to energy weapons, missiles, and in a pinch Gauss rifles. Instant motivation to try to "fix" them right there.

[willydstyle]

Because people like the idea of having big loud honkin' guns on their war machines, yet in actual terms of game mechanics autocannons are generally considered to suck next to energy weapons, missiles, and in a pinch Gauss rifles. Instant motivation to try to "fix" them right there.

When not using Clan Tech, I actually find the AC10 and LB 10X to be pretty comparable to the other tech in the era.  For example, two PPCs and 10 heat sinks (to make them heat efficient) in intro-tech does 20 damage, weighs 24 tons, and has a bit more range  on the AC10.  A PPC, AC10, 1 ton of ammo, and 3 heat sinks in intro-tech does 20 damage, weighs 23 tons (so 1 ton less), has an explosive component, has one gun with slightly less range, but no minimum range will often offset that problem.  The AC10 is a bit of a tradeoff, as it allows a mech that has reached its heat capacity with energy weapons to be slightly more weight efficient as you add more guns, but then has an explosive component.

The LB 10-X similarly compares favorably to ERPPCs.  With DHS, two ERPPCs and an extra 5 heat sinks weighs 19 tons, but finding the critical space for all those heat sinks can be a problem, especially if you're using endo steel or ferro-fibrous (however, they can be wonderful crit-packing!).  An ERPPC and an LB-10X with no additional heat sinks, but two tons of ammo weighs 20 tons, so you're losing out a little on the weight-efficiency department, but you gain wonderful, wonderful cluster ammunition. Being able to crit-seek at 18 hexes is just beautiful.

[monbvol]

I'd still rather have the 2xPPCs.  Sure it may weigh more to have total heat efficiency but if I fore go that and use reasonable firing discipline I can achieve a lot more on a Mech or ASF.  The AC-10 can be used as an okay secondary weapon but I haven't seen a Mech where it is used as a primary weapon where the Mech wouldn't be better off replacing it with something else.  As it exists the AC-10 does have a useful niche, it can be a fantastic main gun on a combat vehicle.

[willydstyle]

I'd still rather have the 2xPPCs.  Sure it may weigh more to have total heat efficiency but if I fore go that and use reasonable firing discipline I can achieve a lot more on a Mech or ASF.  The AC-10 can be used as an okay secondary weapon but I haven't seen a Mech where it is used as a primary weapon where the Mech wouldn't be better off replacing it with something else.  As it exists the AC-10 does have a useful niche, it can be a fantastic main gun on a combat vehicle.

If I'm designing a mech with intro-tech, I'd rather have: PPC, AC10, Medium Laser than two PPCs, because you get more total damage and an extra useful weapon to cover the minimum range on the PPC.

[monbvol]

When you have the tonnage the 2xPPCs will perform better, especially if you tweak the number of additional SHS to trade in Medium Lasers.  Keep in mind though I'm one of those screwball players who doesn't consider it automatically a bad thing to lose movement due to overheating.

If not then yeah the AC-10 in that sort of setup does work well as a secondary weapon.

[BC01]

One thing with autocannons is that they are not all the same thing, the AC20 on a Victor, a Hunchback, and on a Demolisher are all different completely different systems presumably using different ammo so the listings are for a kind of generic class of weapon rather than a specific kind of gun.  In the Gray Death series it is mentioned that the Victor and the Marauder use the same ammo in their cannons, but the Victor fires them in short fast bursts. Another book (I forget which book or even which mech they refer to specifically unfortunately) describes an ac20 that is a low velocity grenade launcher scaled up for mechs.

It is true that PPCs perform better for the tonnage than most autocannons, though the AC2 is handy for drawing units out of certain types of cover by plinking at the defenders beyond the range of their weapons.

[rlbell]

There is no good reason for minimum ranges on autocannons....or any other direct fire weapon.  Arming of LRM warheads is the only one that makes sense.  We have always played with no minimum ranges for direct fire weapons.  This helps the AC/5 in a 3025 game.

But nothing can help the horrible AC/2

Numbers, careful aiming, extra range brackets, allowing mechs with multiples of the same weapon to use the Strat Ops bracket fire rules (it seemed like a good idea*), and defending a hardened building against mechs marching across a dropship landing field (featureless waste of pavement over a hundred hexes across) go a long way to making the AC/2 a terror.  The assault looked like it might get beaten back, before things got to the minimum range and the defenders were routed.

* I am running a campaign where the players are sent into the sharp end when things are going wrong.  The rebels have more mechs than pilots, and they are each a 100t battlemech, but 8x AC/2's on a 2/3/0 chassis does not equate to an assault mech, even if the armor is maxed.  The B4S Pom-pom was an infantry support and AA mech, and was probably obsolete when it was built to support a doctrine that tried to keep large infantry formations relevant.  I selected a group of optional/house rules to make them a potential threat.

[massey]

AC-2s aren't the greatest weapon, but in 3025 they are okay.  Longest ranged weapon in the game, great range brackets, and they're fighting opponents that don't have that much armor.  Besides weapons like the Clan ER Large Laser, what really hurt the AC-2 was Endo Steel, because it gives players a bunch of extra tons that almost immediately goes to armor.  Add to that rules changes to make vehicles more survivable and the AC-2 sees its role disappear.

[Cannonshop]

AC-2s aren't the greatest weapon, but in 3025 they are okay.  Longest ranged weapon in the game, great range brackets, and they're fighting opponents that don't have that much armor.  Besides weapons like the Clan ER Large Laser, what really hurt the AC-2 was Endo Steel, because it gives players a bunch of extra tons that almost immediately goes to armor.  Add to that rules changes to make vehicles more survivable and the AC-2 sees its role disappear.

And I'll counter that statement with this one:

Two points that hit will remove more armor than 30 that miss.   The real problem with the AC/2 is most of the platforms it's installed on:

Slow, and limited.

The best platforms for AC/2 employment are vast and use the VTOL hit tables-the reason is that that 2 point weapon can, on a quick moving unit, one not hampered by terrain restrictions, in the right hands hit all day, while NOT being hit in return.

It's your range brackets-the AC/2's Medium overlaps with quite a few bigger hitters' LONG range, and on a fast platform that uses its high cruise speed, that ends up putting the other guy at 9 before he adds gunnery to return fire, while the VTOL's running 7's and 8's (or less, with PA).

Hitting MATTERS.  Any weapon that helps your side hit without taking hits, is a net positive to winning the fight.

[MoneyLovinOgre4Hire]

Well said, Cannonshop.

[monbvol]

And that's why I give grudging respect to the AC-2.  The sheer range means if you don't play on postage stamp sized maps it can be a very useful long haul weapon.  I'd still love to see it weigh less but I still respect the range.

[Stride]

I don't agree with that argument. Weapons are not built with the best of everything for every situation. Designers often make compromises to help weapons excel in one area at the expense of others.

i've just considered it a firmware 'feature'. same basic flavor as cray's thoughts. AC2 and 5 are designed as complete packages for long range solutions.

my house rule is that any ac2 or 5 can be switched to its 'light' stats in the end phase.