What is it with AC/5s and SRMs/LRMs on everything?

[Daemion]

Seriously, since tanks don't have worry about heat output, why aren't there more designs fielding the better mid-ranged gun - the AC/10? I can think of only two right off hand. The Patton, and I believe the Zhukov. Everything else either runs AC/20s or AC/5s.

So, what is it with the game designers and this love affair with the AC/5 and some of the more questionable missile classes.

For some reason, LRM 10s, while a better 5-point damage weapon than the AC/5 (they actually get a wayward 6th point more often than not) still seam like a waste to me more often than not.  Best used in at least pairs. I'd Almost rather spam 'em with a bunch of LRM 5s or go for the larger damage potential in the LRM 15 and 20.

Missiles, in general, while having interesting niches, seam a little out of sorts. They don't have the stopping power that we see in modern day missiles, and they generally do an average damage amount for a limited time. You can get a similar effect with a bunch of lasers aimed at the same target. Still, indirect possibilities with LRMs and the crit-seaking and incendiary delivering options in SRMs in a single package with relatively low heat output gives them a leg up over the AC/5.


It would make sense to me that something with the speed of the Vedette could handle the shorter range yet extra punch of the AC/10. I sometimes wish that the very common Demolisher had a pair of AC/10s and more armor or better speed. They get shot to pieces far too readily before they can get those heavy guns into a position to use 'em.

And, Vedettes need way too many numbers on the field to be really worth the gun they have on them. A full company wouldn't worry any but the lightest BattleMech lance, and maybe not even then. Heck, a company of Vedettes versus a company of Vedettes might take a while to play out since most of them are going to be rendered  immobile before any of them are close to dying from an armor breach.

And, then there are all those medium Mechs sporting said weapon. All. Those. Mechs.

Even being cheep and ready just doesn't justify the failings of the AC/5 and ammo-based weaponry in general, over centuries of use in vast numbers. At one point in BT history, the AC/5 was actually worth something, and a good weapon to have. That isn't the case in modern combat, unless there's an aspect that we just aren't seeing, where the AC/5 is still a potent weapon, but not in armored combat against top-of-the-line forces.

So, why do the game designers still flood the playing field with these weapons in a large number of chassis in seemingly almost universally similar configurations?

[Sir Chaos]

There was a time, early on in the franchise, when the AC/5 was actually the only autocannon that existed. Which might explain why designs from that time do not carry any other autocannons.

Or so I am told - that was way before my time.

[JadeHellbringer]

There was a time, early on in the franchise, when the AC/5 was actually the only autocannon that existed. Which might explain why designs from that time do not carry any other autocannons.

Or so I am told - that was way before my time.

Absolutely true, pre - TRO:3025. Note that nothing in the original box set has anything but the AC-5.

(That said, one of Battletech's best cheap-and-nasty tanks is the Po, which is an AC-10 on treads with a sheath of armor and a couple of MGs. Ditto for the Gladius, which replaces the MGs, treads, and armor with hoverskirts and a cupholder for the crews' brass balls. Underestimate either at ones' own risk.)

[Kit deSummersville]

There was a time, early on in the franchise, when the AC/5 was actually the only autocannon that existed. Which might explain why designs from that time do not carry any other autocannons.

Or so I am told - that was way before my time.

CityTech introduced the other classes of Autocannon. I have no idea what designs Daemion thinks are "still" flooding the playing field these days though....

[klarg1]

It is true, but all the AC/5 'mechs from the 2e boxed set add up to all that many designs, and, as Kit pointed out, Citytech came along and introduced the other sizes right afterwards.

 Were the handful of 'mech designs in the original house sourcebooks limited to just "autocannon" for long ranged ballistic options?


 

[JadeHellbringer]

As far as I know, yeah, it was 'autocannon' (AC-5) or machine gun for ballistics. I can't think of anything else anyway- no other calibers, no Ultra/LBX/RAC, no Gauss of any flavor, etc.

[Tymers Realm]

I'd also say the increased weight (4T) and half of the shots per ton would also be a damper on wider use of the AC/10 over the AC/5.

[massey]

My head-canon is that ACs have always had access to most of the alternate munitions.  And in "real life" terms, you probably don't have to allocate it in full-ton lots.  So let's say you have an AC-5 that normally has 20 shots per ton.  You might carry 14 normal shots, 4 flechette rounds for dealing with infantry, and 2 flak rounds in case you see a jet fighter.

If that's the case, then an AC is a wonderful weapon.  You've got some versatility that other weapons don't give you.  Sure, they aren't jaw-droppingly excellent, but they're pretty good and they're worth having.  The AC-5 has good range and fairly deep ammo bins.  Sometimes you don't need a massive hole-puncher, you just need something to do consistent damage.

I think AC-5s are probably the weapon of choice for low intensity warfare.  As I recall in the original Battledroids, jeeps took 5 points of damage to destroy (it was kind of unclear whether it took 5 or 6 points to destroy a jeep, based on the wording).  A lot of battles aren't fought by evenly-matched sides duking it out.  A lot of battles are fought by one side with way more stuff stomping on an under-equipped opponent.  I think a lot of medium mech designers had a purpose in mind, and that was to blow up a lot of guys weaker than you.  Maybe the Hermes II was supposed to spend all day blasting jeeps into oblivion.

[Garrand]

And, Vedettes need way too many numbers on the field to be really worth the gun they have on them. A full company wouldn't worry any but the lightest BattleMech lance, and maybe not even then. Heck, a company of Vedettes versus a company of Vedettes might take a while to play out since most of them are going to be rendered  immobile before any of them are close to dying from an armor breach.

Just a quick point on the above. I know Battletech is a game, & we all like to stand and fight to the last glorious moment, and every immobilized tank becomes a bunker and a grave for 4 brave soldiers. But in a "real life" conflict, if you render inoperable one of the prime assets of armor (mobility, firepower & protection are the other two), then it is altogether likely that the crew will jump out the hatches, pop smoke, and proceed at best possible speed to the rear if their track is immobilized. So even though those Vedettes aren't going anywhere under their own power, they are now "mobility kills" & become the spoils for whomever holds the battlefield afterwards.

Damon.

[Lorcan Nagle]

Just a quick point on the above. I know Battletech is a game, & we all like to stand and fight to the last glorious moment, and every immobilized tank becomes a bunker and a grave for 4 brave soldiers. But in a "real life" conflict, if you render inoperable one of the prime assets of armor (mobility, firepower & protection are the other two), then it is altogether likely that the crew will jump out the hatches, pop smoke, and proceed at best possible speed to the rear if their track is immobilized. So even though those Vedettes aren't going anywhere under their own power, they are now "mobility kills" & become the spoils for whomever holds the battlefield afterwards.

Damon.

If you play using the forced withdrawal rules, that's exactly what happens, too.

[Sir Chaos]

The upside of the Vedette´s lousy firepower is that it is usually pretty survivable as part of a mixed force, since the enemy has plenty of more threatening targets to shoot at most of the time.

Would you rather fire back at the Vedette that´s plinking at you from 12 hexes, or at the Demolisher which is approaching effective range of its monster cannons?

[worktroll]

There shouldn't be any argument about the efficiency and utility of LRM and SRM carrying designs.

The LRM has range, and it has indirect fire. These two things are pearls of great price (albeit usually not together in the same shot ;) ). They're at a mid-level in terms of weight and heat. Look at pretty much any AC-5 carrying design, and replace the cannon with a LRM-15 plus additional ton of ammo. Jagermech JM6-AA, I rest my case. Heck, look at the over-heated designs, and replace the PPC with LRMs. Not as good a swap - 10 solid points of damage has its own power - but it's still worth considering.

SRMs are the low-heat alternative to banks of medium lasers, and also represent your best cluster hit rolls in lower-tech play. Plus the ability to drop inferno rounds on infantry from outside their (old-game) range. Plus, on the whole, SRMs are far more "ammo efficient" than LRMs - it's easier to carry "enough" rounds for an engagement in a single ton.

But yes, the march of progress did leave the ACs in the shade. OTOH, the LB-X restored enough shine for me - the LB-10X is a wonderfully versatile weapon, provided you can carry 2 tons of ammo.

W.

[Sartris]

the AC/5 is hardly slapped on everything. In the history of all canon vehicles ever, there are only nineteen AC/5-toting units, and three quarters of those have intro dates before 3010

The "glut" of them comes from TRO 3025/26 - Scorpion, Scimitar, Condor, Vedette, and Partisan (plus AC/5 variants of the Pike and Schrek that came later) - all fluffed as "value" militia units or skirmishers (or an AA platform in the Partisan). The majority of the rest are units from the Age of War like the Marsden and Merkava backfilled to give some life to the era.

If this is a love affair, the AC/5 should break up with TPTB and find someone who will call them more often.

[The Eagle]

If you play using the forced withdrawal rules, that's exactly what happens, too.

Where can I find said rules?  I'm interesting in anything that produces more realism.


On topic, though, I actually don't terribly mind the Ultra and LBX 5-class autocannons.  They retain their good range and both add value.  They're not my first choice in weapon by any means, but I don't morose when I pull a 3050 upgrade of the Hermes II, for example.

[Scotty]

I actually rather like the UAC/5.  It's two tons heavier than a PPC, sure, but it puts out 3 tons of DHSs worth less heat for a net wash with a ton of ammo included.  You get less damage, but you get some critseeking, and you get a better range than a PPC with no minimums.  It works well as a long range secondary weapon to a design with a high heat primary weapon load.

[Sartris]

Where can I find said rules?  I'm interesting in anything that produces more realism.

Total Warfare pg 258 / BMM pg 81

[OpacusVenatori]

I actually rather like the UAC/5.  It's two tons heavier than a PPC, sure, but it puts out 3 tons of DHSs worth less heat for a net wash with a ton of ammo included.  You get less damage, but you get some critseeking, and you get a better range than a PPC with no minimums.  It works well as a long range secondary weapon to a design with a high heat primary weapon load.

You forgot the chance to jam.

[Scotty]

25% chance to jam over the course of a ton of ammo if every shot is fired double.  I'll take my chances.

[grimlock1]

25% chance to jam over the course of a ton of ammo if every shot is fired double.  I'll take my chances.

I'm not sure I track your math.  The first ultra shot will jam on 2d6=2 or 2.8%.  The second ultra shot will jam on 3 or less, or 8.4%.  The third has a 16.7% chance to jam on 4 or less. Firing 3 consecutive ultra shots has a cumulative chance to jam of 27.9%.

Graveyard shift may be rotting my brain so be gentle with the cluebat.

[Hellraiser]

Were the handful of 'mech designs in the original house sourcebooks limited to just "autocannon" for long ranged ballistic options?

The only mechs introduced in the house books were the Raven & Cataphract in Liao, and the Cat packed an AC10, so no.

[Hellraiser]

I'm not sure I track your math.  The first ultra shot will jam on 2d6=2 or 2.8%.  The second ultra shot will jam on 3 or less, or 8.4%.  The third has a 16.7% chance to jam on 4 or less. Firing 3 consecutive ultra shots has a cumulative chance to jam of 27.9%.

Graveyard shift may be rotting my brain so be gentle with the cluebat.

Not sure if you are thinking of MASC or RACs or what, but Ultras only ever jam on Snake Eyes - 2.

I think what he's saying is you only have 10 chances to jam in 1 ton which comes out to be 27.78% chance of getting a jam.

[Scotty]

I'm not sure I track your math.  The first ultra shot will jam on 2d6=2 or 2.8%.  The second ultra shot will jam on 3 or less, or 8.4%.  The third has a 16.7% chance to jam on 4 or less. Firing 3 consecutive ultra shots has a cumulative chance to jam of 27.9%.

Graveyard shift may be rotting my brain so be gentle with the cluebat.

Ultras only ever jam on snake eyes, a 1/36 chance.  The chance of not jamming is 35/36.  Firing for 10 turns at Ultra ROF, you have (35/36)^10, which works out to a 75.44% chance to not jam (simple math reveals the chance to jam, therefore, is a 24.56%) during the entire ton of (AC/5) ammo.  An Ultra/10 can burn through a ton of ammo with a jam chance of less than 14%.

I'll take those odds for a near 50% increase in damage over a comparable AC or PPC.

[grimlock1]

Ultras only ever jam on snake eyes, a 1/36 chance.  The chance of not jamming is 35/36.  Firing for 10 turns at Ultra ROF, you have (35/36)^10, which works out to a 75.44% chance to not jam (simple math reveals the chance to jam, therefore, is a 24.56%) during the entire ton of (AC/5) ammo.  An Ultra/10 can burn through a ton of ammo with a jam chance of less than 14%.

I'll take those odds for a near 50% increase in damage over a comparable AC or PPC.

Are you assuming nonconsecutive ultra shots? 

Also of the odds of not jamming are (35/36)^10, shouldn't (1/36)^10 give the odds of jamming?  I get 2.74x10^-16.

[Scotty]

There's literally no difference between consecutive and non-consecutive shots.  It's not like MASC or a Supercharger or Radixal Heat Sinks.  Snake eyes every single time.

If you take 1/36, that's the chance that a gun does jam, which means taking it 10 times is measuring the odds of jamming it on 10 consecutive rolls.  That's why the number you got is so low.  2.74 x 10^16 can be expressed as a real number as: 0.000000000000000274.  That's..... very low.

[Sir Chaos]

Are you assuming nonconsecutive ultra shots? 

Also of the odds of not jamming are (35/36)^10, shouldn't (1/36)^10 give the odds of jamming?  I get 2.74x10^-16.

(1/36)^10 is the probability that it jams EVERY time on ten rolls.

For things like this, you calculate the probability that you shoot ten times without jamming, (35/36)^10, and subtract that from 1. You end up with a chance of 75.45% of firing the gun in ultra mode ten times without jamming, i.e. a 24.55% percent chance that it will jam before the ton of ammo is used up.

[Kit deSummersville]

(1/36)^10 is the probability that it jams EVERY time on ten rolls.

Them thar is Hellbie odds.

[Sir Chaos]

Them thar is Hellbie odds.

IIRC even Hellbie only got 7 out of 10.

[JadeHellbringer]

IIRC even Hellbie only got 7 out of 10.

On turn #1. With three remaining guns, it didn't really survive long enough to jam the others. Given time, I'm sure I'd have been able to finish the job and leave it with just the MGs. (Actually I was almost hoping he'd get a TAC, float it to the right arm - where the three usable guns were - and roll a 12 to blow it off, just for the sheer ARGH value.)

[Hythos]

While an intense fire-fight may take 30-40 seconds, the war of attrition is won by at out-ranging & out-lasting the enemy.
310-360m is the sweet-spot for the Autocannon-wielder over that of the Large-LASER boat.

Too many pilots plan for a short brawl because they don't have the endurance to carry on for several minutes ;)  This is why the SHD-2H pilots jog 5-10 miles a day.

[Kidd]

Missiles, in general, while having interesting niches, seam a little out of sorts. They don't have the stopping power that we see in modern day missiles, and they generally do an average damage amount for a limited time.

Uh, nearly NOTHING in Battletech has stopping power equivalent to IRL weapons. And I LOVE the crit-seeking power of massed SRMs.

The AC-10 is nice, yes, but sometimes one just doesn't have the tonnage to fit both an AC-10 AND another weapon system... so AC-5 it is. The AC-5 gets much more attractive once alternate munitions (specifically precision ammo) comes along... not to mention the LBX and Ultra varieties