I have been into 40K since 2nd ed, and have been translating weapons just by my gut feeling, rather than any sort of system.
I am however, stuck at the Rocket Launcher.
In 40K, a fragmentation missile does the same damage as a bolter shot. (3d8 in my game. Lasguns are doing 2d8).
3d8. I checked out d20 modern, and the LAW does 10d6. TEN D-SIX!. Holy crap!.
So, should I crank up the rocket launchers damage to 10d6, and be un-faithful to the game I am trying to convert? Or just keep it at 3~4 D8, and not have the LAW exist? Or keep the LAW, as it is disposable, and crank up the purchase DC, having it more as a Davey-Crocket type weapon?
Opinions please.
Now comes the problem of 40k's weapon fluff compared to RPG mechanical balance. The thing you have to remember about 40k's gear is that its VASTLY more powerful than anything we have today. A single Space Marine is supposed to be the equivalent of the entirety of today's US Army, by the fluff.
Lasguns are supposed to be able to punch a hole through a modern tank according to their fluff, and should be no weaker than a 50 cal.
A bolter is like a miniature rocket launcher, they should honestly be just as powerful as the LAW.
The rocket launcher? You're looking at something that should be as powerful as the cannon on the Abrams.
This is all assuming you're going by 40k's fluff portrayals of the equipment and not by the vastly toned-down play mechanics.
I'd say the Lasgun is the 40k equivalent of the modern day 5.56 assault rifle. Equivalent. NOT equal to.
The 5.56 would never stand a chance of penetrating anything in the 40k world, and even the puny lasgun does have... well... a chance...
Have you looked at Dark Heresy if you wanna play 40k RPGs? It's really neat - I GM both a d20 Modern and a Dark Heresy campaign ATM.
The real issue here is balance. You're gonna need to find out how you wanna balance your system. Are you going by the tabletop rules when converting? Because then, you're going to have some issues. By novel fluff? Issues too...
I checked out d20 modern, and the LAW does 10d6. TEN D-SIX!. Holy crap!.
The LAW would be the equivalent of a krak missile. The krak missile causes damage through implosion, so while it will tear up a large sturdy target (essentially turning it's structural strenght against it), it is effectively limited to damaging a single target.
I'd suggest using 10d8 bludgeoning for a krak missile and 4d8 slashing (Ref 15 for half, 20 or 30 ft. burst radius) for a frag missile.
-DF
Doesn't Autogun also mean that the cannon doesn't have to be manually reloaded after each shot... My campaign houserule is that depending on the RoF the weapon has selected you multiple for each round and for HRoF like gatling guns roll a percentile to see how many rounds are wasted/hit 45% of 600RpM equals a little under 300 rounds...
No, in 40k, Autogun means solid-projectile assault rifle.
300 rounds in a single burst with 600 RpM? What!? That's.... 60 bullets per second? You're gonna need a minigun for that kind of RpM - several thousands RpM...
... which I am modifying for an A.I. Anti-Personnel/Fortification TankWhy don't you use Wikipedia? Or Google?
http://en.wikipedia.org/wiki/GAU-8_Avenger
But the GAU8 isn't a gattling gun. It's a rotary cannon.
50 Bradley Bushmaster25mm shoot at you
but doing much much more damage.
WH40k
While stating up weapons you have to consider the relationships between all weapons of that setting and armors of that setting. What is the point of wearing a 1971 flackjacket if just about every gun of the setting can punch thru armored cars?
So we would have to say that the guns of the setting are far more damaging than y2k guns and y2k armors, which then implies the 40k armors would have to be better than y2k armors. Technology imparts power creep, y1800 flintlocks & blackpowder cannon get horrid stats compared to y1900 guns and it will be even more pronounced over a 38k term.
That leaves us with the problem of accepting the fluff of technology power creep making 40k setting weapons insanely powerfull and armors insanely impervious. Now have KungFuJoe try to kick IronMan in the face and you see a problem.... give KungFuJoe a 12lb slegde to clobber Ironmans head a few times, and Ironman still wont even spill his beer.
Ironman then will slightly glance Joe with his VibroMonoPowerLaseChainToothbrush and do 1d2+35d6 damage 50%break chance
Which means for anyone to survive more than 10 minutes that have to be in armor and that armor has to give SERIOUS hardness/dr-er numbers
Or you can tell the setting fluff to switch to Decaf
and just recalibrate the entirety of the game damages to Bolter=3d6 and set all other weapons & armors to be in setting scale to that.
Assuming a bolter does 3d6 (or 3d8 or whatever), just scale it up and down from there. A Lasgun might do 2d6 pr 3d4 or whatever. You might want to make a Bolter bolt pretty deadly. I'd say around 3d10. But that's just me.
3.900 RpM.
Why don't you use Wikipedia? Or Google?
http://en.wikipedia.org/wiki/GAU-8_Avenger
But the GAU8 isn't a gattling gun. It's a rotary cannon.
Forgot about the link in my Fav folder... thou thanks for the reminder