Rotary AC's: Rules vs House Rules

[Black_Knyght]

Over time I've heard a number of widely varying opinions on RAC's and this has got me to thinking about their possibly inclusion in OUR current campaign.

I was wondering what the good folks around here thought of the canon rules handling them?

Also if anyone used any "House Rule" to alter RACs in some way? And IF so, how?

[Nightgaun7]

http://bg.battletech.com/forums/index.php?topic=51796.msg1212430#msg1212430

[Legion]

I mentioned my preferred solution in the linked thread, but I'll restate it here:  Allow AP ammo (I should also note that I don't apply the +1 to-hit penalty).  Gives a potentially terrifying new meaning to "spray and pray", if you can find the space for all that ammo!

[mike19k]

I like to let them roll for each round to hit. Pro - makes it more likely that they will hit more, Con - makes it more likely they will jam, as if any single roll is a jam the weapon is jammed.

[Legion]

I like to let them roll for each round to hit. Pro - makes it more likely that they will hit more, Con - makes it more likely they will jam, as if any single roll is a jam the weapon is jammed.

Wouldn't this only make them more likely to hit if you've got a good target number?  Also, that increase in chance to jam seems a bit steep for my liking.

[Black_Knyght]

Given how modern rotary cannons have long since overcome the jamming issues of the older "Gatling" style guns, our GM has personally decided to allow them to fire like any other weapon with the following changes:

Using the RAC requires a separate 2d6 roll every time it's fired. If you roll "snake eyes" it jams but is clear-able, and if you roll "box cars" it jams too badly to clear in the field. Anything otherwise and it doesn't jam at all. It's also incompatible with targeting computers given the nature of it's "rapid spray" RoF (like trying to use a laser sight with a machinegun firing at full-auto).

[mike19k]

Wouldn't this only make them more likely to hit if you've got a good target number?  Also, that increase in chance to jam seems a bit steep for my liking.

If you need a four to hit, you get up to six tries to so likely that you will get six hits, if you need an eleven to hit it also gives you six tries to get a hit making it more likely that you will get a hit. Compare this to how it is now if you need the four to hit, you then roll on the cluster to hit, making it very unlikely that you will hit with all six, if you need the eleven to hit then there is almost no chance that you will get a hit, but if you do yes it is likely that you will get more hits then if you rolled each.

[Legion]

Given how modern rotary cannons have long since overcome the jamming issues of the older "Gatling" style guns, our GM has personally decided to allow them to fire like any other weapon with the following changes:

Using the RAC requires a separate 2d6 roll every time it's fired. If you roll "snake eyes" it jams but is clear-able, and if you roll "box cars" it jams too badly to clear in the field. Anything otherwise and it doesn't jam at all. It's also incompatible with targeting computers given the nature of it's "rapid spray" RoF (like trying to use a laser sight with a machinegun firing at full-auto).

I don't like this at all, but for one picky reason:  Rolling double-6 should NEVER, EVER be a bad thing!  ;)

[Black_Knyght]

ROFLMAO - That was our initial reaction too!

But his explanation for it made sense, so we all went with it in the end. Works out well, surprisingly, and still allows an element of risk to RAC's.

[Legion]

If you need a four to hit, you get up to six tries to so likely that you will get six hits, if you need an eleven to hit it also gives you six tries to get a hit making it more likely that you will get a hit. Compare this to how it is now if you need the four to hit, you then roll on the cluster to hit, making it very unlikely that you will hit with all six, if you need the eleven to hit then there is almost no chance that you will get a hit, but if you do yes it is likely that you will get more hits then if you rolled each.

After I posted I had doubts about my own assumption, so I ran some numbers and you're right, rolling to hit for each shot increases your average potential damage by 1.5x (for a 6 round burst, for all to-hit numbers), since you're guaranteed to avoid bad rolls on the cluster table.  Interesting, I still think the increased jamming sounds problematic, but this idea has merit.

ROFLMAO - That was our initial reaction too!

But his explanation for it made sense, so we all went with it in the end. Works out well, surprisingly, and still allows an element of risk to RAC's.

I'd be tempted to say that a roll of 2 means the weapon is jammed too badly to clear, and a roll of 3 means it is jammed but can be cleared.  A little worse odds than the way you're playing it, but it just feels more...right.  ::)

[idea weenie]

I like to let them roll for each round to hit. Pro - makes it more likely that they will hit more, Con - makes it more likely they will jam, as if any single roll is a jam the weapon is jammed.

So roll to-hit for each shot, then use Legion's idea where on a 3 the weapon jams but can be cleared in the field, and on a 2 it is stuck like that until back at the base?  I like it.

[Black_Knyght]

I'd be tempted to say that a roll of 2 means the weapon is jammed too badly to clear, and a roll of 3 means it is jammed but can be cleared.  A little worse odds than the way you're playing it, but it just feels more...right.  ::)

It was an issue for a bit with us too, until our GM made the point that snake-eyes and box-cars are just two sides of the same thing, and that most people's gut reaction to that is more a matter of "traditionally accepted convention" than any real differentiation. One is the lowest possible double, the other the highest possible double, but the odds of getting either are actually the same.

[VanVelding]

The Big, Red Die. The system is that you roll 1D6 on a red die, then roll another D6 for each cluster on different colored die. Each cluster that hits when you add it to the red die hits. Then, you take the red die and the clusters that hit and re-roll them to determine the hit location. Any result of '2' jams the RAC, so more clusters automatically means a higher chance to jam.

I haven't done extensive testing with RAC's, but it's worked well enough for LRMs and LBX ACs.

[idea weenie]

The Big, Red Die. The system is that you roll 1D6 on a red die, then roll another D6 for each cluster on different colored die. Each cluster that hits when you add it to the red die hits. Then, you take the red die and the clusters that hit and re-roll them to determine the hit location. Any result of '2' jams the RAC, so more clusters automatically means a higher chance to jam.

I haven't done extensive testing with RAC's, but it's worked well enough for LRMs and LBX ACs.

It also means that the fewer hits you get the less likely you are to jam.  So you could fire 6 shots at a to-hit of 8 and roll a '1' on the Big Red Die, then none of the shots will hit, along with none of them causing the gun to jam.

[TigerShark]

If you're using BV, remove the jamming capability from the RAC. Jamming is not calculated in the BV of the weapon, so you are paying in BV for the average damage of a hypothetical LRM-30, but with a drawback that makes it too risky to use. Scrapping the jam means you're getting what you already paid for. ::shrug::

http://www.heavymetalpro.com/bv_calc.htm

LRM-30 231 BV (29 per ton of ammo):
5/10/15 range (no min)
30 damage max (18 average)
1 damage/missile (30 shots)

RAC/5: 247 BV (31 per ton of ammo)
5/10/15 range (no min)
30 damage max (20 average)
5 damage/hit (6 shots)

As you can see, the fake "LRM-30" is every bit as good as the RAC/5, and then some. For LESS BV, you get indirect fire, varied ammo types, and smaller ammo bins. The RAC/5 has less heat, but becomes practically useless in a fight once it jams, unless your opponent is slow enough to allow you to take two turns hiding / unjamming while not firing. It's quite silly and I never play with jamming anyhow.

Even if you're not going with "no jamming," then scaling back the jamming brackets goes a long way in making up for lost BV:

1-3 shots = no jam
4-5 shots = jams on 2
6 shots = jams on 3

[Black_Knyght]

THAT makes the most sense yet of everything I've heard.