Weapon Damage


Can anyone explain to me why on Earth a 9mm and a 10mm weapon both do 2d6 damage? The 10mm really should do more damage than that! What about 15mm and 20 mm handguns, how much would they do?
?? Not sure but I think (if I can remember) the difference is penatration ability not damage ex. a 9mm will bounce off of a winshield of a car and be deflected at a angle where the larger bullets will not be deflected as much
Okay, so then if it's a matter of penetration a 10mm round really should do more damage than a 9mm. While the slug may not be all that much bigger, there is a good amount more powder to burn. That gives you a higher muzzle velocity and thus better penetration. It just makes no sense to me that they'd do the same damage.

I guess that's why I liked the old Underground RPG's damage. Sure it took a bit more rolling of the dice but I thought it made more sense. The wound inflicted was based on the penetration value of the round. Roll a Penetration skill check and the quality of the result gave you the type of wound. Hmmm, probably could do something similar in d20...
Well OGL Cybernet is based off d20 Modern and the coarse grainularity of fitting all calibres into 5 types (2d4, 2d6, 2d8, 2d10, 2d12) comes from that. The idea is that the your choice of weapon comes down to style, not the one that does the most damage (though the 5Sevens in Ultra Modern Firearms skew this a bit :D ). Here is an article by Charles Ryan on the subject (http://www.wizards.com/default.asp?x=d20modern/bp/20030218a).

15mm & 20mm guns would be in the 2d12 range (putting it at the same power as a berrata light fifty). Edit: Just double checked in OGL-C and light fifty does 4d6.

Penetration could probably be modeled by giving armor a form of DR against certain grades of ammo (either by calibre or by damage dice) with armor piercing rounds doing extra damage (thus negating some of the DR) or being treated as a a higher calibre or damage dice.