And .308 JHP instead of HP, that sound right.
But then you need to add -5DT to 5.56mm as they should.
I think you're on to something here. I decided to get out the slide rule and make a few calculations. I thought I would list the energy available for each round in the game (energy = mass x velocity
2, expressed in foot-pounds), based on common loadings at standardized SAAMI pressures:
Pistol/SMG rounds from a short (<10') barrel @ 25yds.22LR - 120'#
9mm - 310'#
10mm - 400'#
.357mag - 480'#
.44mag - 790'#
5.56mm - 990'#
12.7mm - 1260'#
.45-70G - 1650'#
Carbine/Rifle rounds from a long (>20') barrel @ 100yds.357mag - 715'#
5mm - 860'#
5.56mm - 1000'#
.44mag - 1015'#
.45-70G - 1830'#
.308 - 2300'#
.50BMG - 12090'#
As you can see, there is an incredible amount of difference in the energy available to defeat armor and damage a target from round to round. You'll see I ranked them by energy. I feel this should corralate very closely to the base damage of the weapon firing that round. As far as armor penetration goes, bullet design and area cross section mean a whole lot. If you divide the energy available by the cross sectional area, you have a good idea of the penetration potential of that round (ft-lb/in
2):
Pistol/SMG rounds from a short (<10') barrel @ 25yds.22LR - 3157
9mm - 3163
10mm - 3200
.357mag - 4800
.44mag - 5197
12.7mm - 6428
.45-70G - 10377
5.56mm - 25384
Carbine/Rifle rounds from a long (>20') barrel @ 100yds.44mag - 6677
.357mag - 7150
.45-70G - 11509
5.56mm - 25641
5mm - 28666
.308 - 31081
.50BMG - 61683
As you can see, things kinda makes sense. Faster smaller bullets put more energy on a smaller area, and therefore should have an easier job of penetrating protection. It looks to me like it falls nicely into about three distinct ranges: less than 12000, around 25000-32000 and then 60000. Base ammo DT bypass could be applied to these groups, ie: group one, no bypass; group 2 good bypass; group 3, holy crap, it exploded bypass. And this makes sense. All the big, slow pistol rounds would have no bypass, while the high velocity rifle rounds would have a good amount of bypass while the huge machinegun round that can penetrate .5in thick steel in real life would go through anything.
Bullet design would also have an effect on this. Both the shape of the bullet and the composition of the bullet also helps/hinders armor penetration. Here's a list of bullet shapes in ascending order (poor to good) of penetration capability:
Hollow point - .22,HP .308HP, .357HP, .44HP, .45-70HP, 5mmHP, 5.56mmHP, 9mmHP, 10mmHP, 12.7mmHP
Semi wad-cutter - .44SWC, .45-70SCW
Flat nose - .357JFP
Round nose - .22, .22plinking, .357, .38special, .44, .44special, .45-70, 9mm, 10mm, 12.7mm
Spitzer (pointed) - .308, .308JSP, .308AP, .50MG (all), 5mm, 5mmAP, 5mmsurp, 5.56, 5.56AP, 5.56surp, .223
So you could give DT bonuses/penalties by bullet shape. Hollow/flats a penalty, round nose no modifier, spitzer a small bonus. You also have bullet construction:
Frangible - hollow points
Unclad - .22 rounds
Semi-jacketed - .308JSP
Jacketed - I assume all non-special ammo (except .22) is jacketed. Maybe not.
Armor piercing - self explanitory
So you could give DT bonuses/penalties by bullet design. If ball (jacketed) is the standard, then JSP, unclad and HP should all have penalties, and AP a bonus.
(I used some pretty ballpark figures for this stuff. I know you guys could find loads that vary greatly from those I've listed, but I've tried to keep things simple and in the middle of the common loads.)Now what does all this mean? Well it could be a guideline to start to balance the weapons. You would need to look at range capability as well as other factors but it's a start. It's all relative also, as any DT bonuses/penalties you assign to ammo has to work with the armor DTs. Take for example, Vault 34 Security Armor. It looks like high quality riot gear. It has a DT of 16. What ammo should we expect to fully penetrate this? Certainly .50mg. And all the AP variants. .308 should do a pretty good job of penetrating, but 5.56mm less so. Let's say you give all .308 -5DT for energy and -3DT for FMJ and -2DT for spitzer. That would take off half of the armor's effectiveness, a pretty good rationalization of what a .308 round *should* do on a kevlar vest.
-Gunny out.