Ballistic Protection standards reference

[swaghauler]

Yes, newer helmets are IIIA, supposedly a few of the later PAGSTs for LE use until the newer designs won out.

I have seen several tests on Youtube of the PASGT helmets and they stop all of the threats that an NIJ Level 3A vest would. This is everything up to mid-velocity .44 Magnum or 12 gauge slugs. They might "ring your bell," but the PASGT would let you keep your brains inside your skull.

[swaghauler]

Degradation Of Armor In The Game

I needed to find a way to take into account the fact that Armor can fail during play. Initially, I just used the Wear Value system but this only gave 10 hits or less. I KNOW (from my own testing) that even soft body armor can take much more than this. The RBR Level 3A Spectra Vest I referenced in my earlier post withstood 26 rounds of .40 S&W 165gr Jacketed Flat Points before letting one through and it is nearly 20 YEARS old with 6 years of daily wear under its belt. I have also seen Demolition Ranch's test of green tip 5.56mm against AR500 armor plate. That plate took 27 hits before a 5.56mm round got through it.

The new system I came up with involves reducing the vest's protection very gradually. I give the vest a "Coverage Rating" based on its actual "Real World" coverage. If a vest covers 80% of your body then its coverage rating is 16 or less on a 1D20 roll. EACH HIT THAT PENETRATES THE ARMOR (resisted hits don't count) REDUCES THIS RATING BY ONE. Thus, a vest with a Coverage Rating of 16 that had 3 rounds penetrate, now only covers the wearer on a roll of 13 or less. When the Coverage Rating reaches 0, the vest is ruined.

For those who want vests to provide 100% coverage to a location (like they do in the basic game), just start with a Coverage Rating of 20 (on 1D20).

Ceramic Vests:

Most ESAPI ceramic plates are NOT "multi-strike" rated. This means that one hit can compromise a plate. There are several instances where single strike plates have stopped multiple rounds. To reconcile this during play, I simply subtract the number of DICE OF DAMAGE OF A GIVEN ROUND from the plate's Coverage Rating for every round that penetrates. This balances out the plate's superior AV without requiring the player to put on new body armor after every hit.

This should add a little life to your player's body armor during play. As always, use what you will and ignore the rest.

Swag.

[Milano]

Umm it has been pointed out to me that the range calculation on the Excel file that I donated earlier is broken. Here is an updated fixed version...

[CDAT]

I needed to find a way to take into account the fact that Armor can fail during play. Initially, I just used the Wear Value system but this only gave 10 hits or less. I KNOW (from my own testing) that even soft body armor can take much more than this. The RBR Level 3A Spectra Vest I referenced in my earlier post withstood 26 rounds of .40 S&W 165gr Jacketed Flat Points before letting one through and it is nearly 20 YEARS old with 6 years of daily wear under its belt. I have also seen Demolition Ranch's test of green tip 5.56mm against AR500 armor plate. That plate took 27 hits before a 5.56mm round got through it.

The new system I came up with involves reducing the vest's protection very gradually. I give the vest a "Coverage Rating" based on its actual "Real World" coverage. If a vest covers 80% of your body then its coverage rating is 16 or less on a 1D20 roll. EACH HIT THAT PENETRATES THE ARMOR (resisted hits don't count) REDUCES THIS RATING BY ONE. Thus, a vest with a Coverage Rating of 16 that had 3 rounds penetrate, now only covers the wearer on a roll of 13 or less. When the Coverage Rating reaches 0, the vest is ruined.

For those who want vests to provide 100% coverage to a location (like they do in the basic game), just start with a Coverage Rating of 20 (on 1D20).

Ceramic Vests:

Most ESAPI ceramic plates are NOT "multi-strike" rated. This means that one hit can compromise a plate. There are several instances where single strike plates have stopped multiple rounds. To reconcile this during play, I simply subtract the number of DICE OF DAMAGE OF A GIVEN ROUND from the plate's Coverage Rating for every round that penetrates. This balances out the plate's superior AV without requiring the player to put on new body armor after every hit.

This should add a little life to your player's body armor during play. As always, use what you will and ignore the rest.

Swag.

Several years ago I went to a body armor shoot, the industry professional told us that to be rated as a level three plate it had to be able to take six shots (not in the same place), but that a level four plate was only rated for a single shot. He went on how just because that is what is required for the rating that does not mean that is the max it would take. They did not have any level four plates there and we wanted to try out our custom tungsten AP .30-06 rounds, so we sent a couple of rounds back with the rep, and they shot the plate (it stopped it) and sent the plate to us, we shot it tell we got one to penetrate (to about six rounds all in the same place). This was all mostly in regards to the ceramic plates, the steel plates were rated the same, but we better able to take the multi-strikes, but were much heavier. We also talk briefly about the polyethlene plates, that at the time could only be made into level III, but doing some looking today they can now be made in level four.

[swaghauler]

Several years ago I went to a body armor shoot, the industry professional told us that to be rated as a level three plate it had to be able to take six shots (not in the same place), but that a level four plate was only rated for a single shot. He went on how just because that is what is required for the rating that does not mean that is the max it would take. They did not have any level four plates there and we wanted to try out our custom tungsten AP .30-06 rounds, so we sent a couple of rounds back with the rep, and they shot the plate (it stopped it) and sent the plate to us, we shot it tell we got one to penetrate (to about six rounds all in the same place). This was all mostly in regards to the ceramic plates, the steel plates were rated the same, but we better able to take the multi-strikes, but were much heavier. We also talk briefly about the polyethlene plates, that at the time could only be made into level III, but doing some looking today they can now be made in level four.

It kind of reminds me of how the manufacturers won't warranty a soft vest older than 5 years because the fibers are supposed to wear out. My old RBR did very well despite nearly 6 years of daily wear and nearly 20 years of existence. I wouldn't have shot holes in it IF I HAD KNOWN IT WOULD STILL STOP ROUNDS LIKE THAT. I was impressed.

[The Dark]

I had been working on my own protection numbers prior to joining the board, since the 2.2 rules have minimal body armor. What I had come up with was that each NIJ type had AV equal to its type (i.e. Type I = AV1, Type IV = AV4). Types ending in A are half a point lower, with subtracted dice rounded down (so Type IIA is AV1.5; against Pen 1 it subtracts 1 die, against Pen 2 it subtracted 3 dice, etc).

Based on some of the tests mentioned by Dr. Bashford Dean in Helmets and Body Armor in Modern Warfare (Yale University Press, 1920), I'd put most trench armor at AV1 with a weight of 19 to 24 pounds. It won't stop rifle bullets up close, but it's moderately effective against pistols and long-range shots from many rifles. It was noted as resisting .30-06 service ammunition (2,780 fps muzzle velocity) at 300 yards, but failing at 60 yards. A low-powered rifle test at 2,140 fps penetrated at 30 yards but did not penetrate at 60 yards.

[swaghauler]

I had been working on my own protection numbers prior to joining the board, since the 2.2 rules have minimal body armor. What I had come up with was that each NIJ type had AV equal to its type (i.e. Type I = AV1, Type IV = AV4). Types ending in A are half a point lower, with subtracted dice rounded down (so Type IIA is AV1.5; against Pen 1 it subtracts 1 die, against Pen 2 it subtracted 3 dice, etc).

Based on some of the tests mentioned by Dr. Bashford Dean in Helmets and Body Armor in Modern Warfare (Yale University Press, 1920), I'd put most trench armor at AV1 with a weight of 19 to 24 pounds. It won't stop rifle bullets up close, but it's moderately effective against pistols and long-range shots from many rifles. It was noted as resisting .30-06 service ammunition (2,780 fps muzzle velocity) at 300 yards, but failing at 60 yards. A low-powered rifle test at 2,140 fps penetrated at 30 yards but did not penetrate at 60 yards.

How do you reconcile a level 2 kevlar vest stopping a 5.56mmN or a 7.62mmN rifle round when Penetration is calculated in Do you change their penetration numbers or damage in any way, or do you just run a "Hollywood" type campaign And don't get me wrong, I have NOTHING against "Hollywood, Space Opera, or High Fantasy" campaigns.... they can be the most fun. I just have a bunch of players who are shooters and combat veterans. They'll call "BS" on anything I introduce that's not based in reality (and this can occasionally be a real pain in the a**). I'd be interested in any changes you have made. I'm still trying to reconcile my AV ratings to stop pistols but not affect rifles as much.

[The Dark]

How do you reconcile a level 2 kevlar vest stopping a 5.56mmN or a 7.62mmN rifle round when Penetration is calculated in Do you change their penetration numbers or damage in any way, or do you just run a "Hollywood" type campaign And don't get me wrong, I have NOTHING against "Hollywood, Space Opera, or High Fantasy" campaigns.... they can be the most fun. I just have a bunch of players who are shooters and combat veterans. They'll call "BS" on anything I introduce that's not based in reality (and this can occasionally be a real pain in the a**). I'd be interested in any changes you have made. I'm still trying to reconcile my AV ratings to stop pistols but not affect rifles as much.

I haven't changed it, although after looking a bit more, I may need to in order to keep high-powered rounds from being less useful. I'm mostly OK with how 5.56mmN interacts, since it only fails at long or extreme range (Dam 3, Pen 1-Nil, so at short or medium 1 die is still getting through). So an M-16 will penetrate up to 110 meters and an M4 at up to 68 meters. 7.62mmN's Dam 4, Pen 2-3-Nil is more problematic, since it won't penetrate at all. I'll need to look into some sort of mechanic for high-powered rounds. My first thought (and totally not playtested) is to give a 1 point penetration bonus for rounds that are either double the armor's value or the armor's value +2 (those are two different options), with a minimum of 1 and no change to Nils (so 1-Nil would remain 1-Nil, 2-3-Nil would become 1-2-Nil, etc). Either would allow 7.62mmN to be considered 1-2-Nil against 1 or 2 point armor, which would let it penetrate Class II up to medium range and Class I up to long range. The difference is that the blowthrough would be at either 3, 4, 5, and 6 or at 2, 4, 6, and 8 for the four classes of armor. My first inclination is to go with 3, 4, 5, 6 to keep most pistols out of the world of armor penetration.

[pmulcahy11b]

I have a PBI I've been rolling around my head for years, but haven't put in any real work on.

Basically, each vest (and ballistic plates, if applicable) type would stop a certain percentage of hits coming in. For every five points of damage stopped (rounding up), one point of blunt trauma is assessed. The old penetration figures stop five more points and assess one more point of PEN listed, and the PC is assessed one point for every five points the incoming round stops.

The problem is the old penetration figures. How to integrate them I know I'm not doing it the right way, but haven't put in the thought to fix it.

Is this a worthwhile idea Should I proceed with it further Does anyone else have any ideas on how this might be fixed

[CDAT]

I haven't changed it, although after looking a bit more, I may need to in order to keep high-powered rounds from being less useful. I'm mostly OK with how 5.56mmN interacts, since it only fails at long or extreme range (Dam 3, Pen 1-Nil, so at short or medium 1 die is still getting through). So an M-16 will penetrate up to 110 meters and an M4 at up to 68 meters. 7.62mmN's Dam 4, Pen 2-3-Nil is more problematic, since it won't penetrate at all. I'll need to look into some sort of mechanic for high-powered rounds. My first thought (and totally not playtested) is to give a 1 point penetration bonus for rounds that are either double the armor's value or the armor's value +2 (those are two different options), with a minimum of 1 and no change to Nils (so 1-Nil would remain 1-Nil, 2-3-Nil would become 1-2-Nil, etc). Either would allow 7.62mmN to be considered 1-2-Nil against 1 or 2 point armor, which would let it penetrate Class II up to medium range and Class I up to long range. The difference is that the blowthrough would be at either 3, 4, 5, and 6 or at 2, 4, 6, and 8 for the four classes of armor. My first inclination is to go with 3, 4, 5, 6 to keep most pistols out of the world of armor penetration.

So I am a little confused, are you talking the NIJ ratings or the in game ratings I think that you are talking the NIJ ratings but even the best soft armor (NIJ 3A) will not stop any rifle round. Or at least out to 100 meters (that is as far as our range at work can shoot), at that distance our M4's go through both sides and the target dummy and into the back stop. Having gone to several body armor shoots from the industries professionals (AKA sales reps) where we got to shoot vests with all kinds of things, not a single vest stopped rifle rounds tell we got to the hard plates.

So I guess I am asking are you trying to get more realistic If so all rifles (not pistol caliber carbines) will penetrate them at just about any range that you can hit with, and even the rifle rated plates are only good for a limited number of hits (level III rated at six, level IV rated at one, but both last longer). Or are you trying to make it less lethal on the players

[swaghauler]

I haven't changed it, although after looking a bit more, I may need to in order to keep high-powered rounds from being less useful. I'm mostly OK with how 5.56mmN interacts, since it only fails at long or extreme range (Dam 3, Pen 1-Nil, so at short or medium 1 die is still getting through). So an M-16 will penetrate up to 110 meters and an M4 at up to 68 meters. 7.62mmN's Dam 4, Pen 2-3-Nil is more problematic, since it won't penetrate at all. I'll need to look into some sort of mechanic for high-powered rounds. My first thought (and totally not playtested) is to give a 1 point penetration bonus for rounds that are either double the armor's value or the armor's value +2 (those are two different options), with a minimum of 1 and no change to Nils (so 1-Nil would remain 1-Nil, 2-3-Nil would become 1-2-Nil, etc). Either would allow 7.62mmN to be considered 1-2-Nil against 1 or 2 point armor, which would let it penetrate Class II up to medium range and Class I up to long range. The difference is that the blowthrough would be at either 3, 4, 5, and 6 or at 2, 4, 6, and 8 for the four classes of armor. My first inclination is to go with 3, 4, 5, 6 to keep most pistols out of the world of armor penetration.

I think you might find the use of a round's Sectional Density rating of value here. Milano has really put in work on integrating "real world ballistics" into the game. SD is determined by the formula:

Sectional Density = bullet weight (in grains)/ [7000 X bullet diameter (in inches) X bullet diameter (in inches)].

Sectional densities range from less than 1 to more than 3 and give shooters a way to rate a bullet's performance on the four sizes of "game animal." Animals (including humans) are broken into four categories known as CPX ratings. These CPX Ratings are:

CPX-1, Varmints: These are animals up to about 50lbs. The Sectional Density used should be above 1 and up to 2.
CPX-2, Medium Game: These include larger sized game that is "thin skinned" up to about 250lbs. Humans are CPX-2 and a Sectional Density around 2.5 is considered a very good "stopper" for a man.
CPX-3, Large Game: These include still larger sized game such as bear, moose, or certain African big game. These animals REQUIRE a bullet with a Sectional Density above 3 for it to be effective in stopping CPX-3 game.
CPX-4, Dangerous Game: This list includes the largest of the dangerous game. Rhino, Elephants, and Hippo's all fall into this category and a bullet should have a Sectional Density of around 3.5 to ensure a lethal hit on these animals.

You could use the sectional density of the round to modify that caliber's Penetration value. I would use the following modifiers based on Sectional Density:

SD of less than 1 = Increase PEN by 1 level (3 becomes 4).
SD of 1 to 1.9 = No increase in PEN.
SD of 2 to 3 = Decrease of 1 in PEN (3 becomes 2).
SD of more than 3 = Decrease of 2 in PEN (3 becomes 1).

I also use a round's Velocity to determine Penetration. I have modified my original chart to take into account real world ballistics AND to better "mesh" with Twilight's integrated Penetration-Damage-Armor Value system.

My Penetration Ratings have changed to the following:

5400fps or more = 1/4 PEN
4000fps to 5400fps = 1/2 PEN
2800fps to 4000fps = 1 PEN
1800fps to 2800fps = 2 PEN
1000fps to 1800fps = 3 PEN
1000fps or less = 4 PEN

I "overlap" my velocity numbers to give the developer/GM the flexibility to round up or down based on a round's real world performance characteristics.

I also allow for modification of PEN for certain designs of ammo. If a round is known for good penetration BUT has a lower Sectional Density (like the various PDW rounds such as .30 Carbine or the 5.7mm X 28mm), you can "swap" Damage for Penetration. The best formula I have found is to Multiply a round's Velocity by X1.5 to find its PEN Number. Nothing is free, though. If this modification to PEN is made, the round's Damage must be recalculated as well. Multiply the Energy of that round by X0.75 to find the new (reduced) DAM of that round at a given range. This is the "tradeoff" for increased PEN. For example:

The 7.62 Tokarev round is well known for its penetration, being able to punch through EVERY cold war helmet and easily penetrating NIJ Level 2A soft armor in its military steel-cored loading. The 90grn steel cored military round averages 1460fps and achieves 426ft/lbs of muzzle energy. Using the formulas above, the 7.62's PEN improves to 2 (from 3) when you multiply 1460fps by X1.5 (2190fps). Its Damage drops from 3d6 (for an energy from 401ft/lbs to 600ft/lbs) to 2D6 (for an energy from 250ft/lbs to 400ft/lbs) when its Energy of 426ft/lbs is multiplied by X0.75 for 319ft/lbs of energy. This gives it the ability to penetrate NIJ Level 2/2A armor (1/2 AV) while still being stopped by NIJ Level 3A armor (AV1) just like it is in real life.

These newer numbers are based on about 3 months of in-game play and seem to be working ok now.

I highly recommend several Youtubers for those interested in Armor Testing and Materials Penetration testing. Check out:

The Military Arms Channel: Tim was the first person to test Dyneema NIJ Level 3 (rifle) armor and has several interesting videos.

The Wound Channel: He was one of the first YouTubers to discover that 3000fps is the threshold for penetrating an NIJ Level 3 (rifle) plate. He also demonstrates that M193 Ball actually penetrates BETTER than the SS109/M855 round. I HIGHLY RECOMMEND HIM.

The Chopping Block: Much like the Wound Channel, He does a lot of armor/penetration testing.

MikeB: He has shot virtually EVERY helmet made in the 20th Century. Go here to see the 7.62T punch through EVERYTHING but the PASGT helmet.

ShootingTheBull.410: This man has test HUNDREDS of rounds in ballistic gel. He is a true authority on "stopping power" as the FBI tests for it.

These are just a few of the better YouTubers out there. There are others such as PocketGunsandGear, TN9Outdoors, ScubaOz, Taofledermouse, and DemolitionRanch. I hope you can use some of this to fix your issues.

Swag.

[swaghauler]

I have a PBI I've been rolling around my head for years, but haven't put in any real work on.

Basically, each vest (and ballistic plates, if applicable) type would stop a certain percentage of hits coming in. For every five points of damage stopped (rounding up), one point of blunt trauma is assessed. The old penetration figures stop five more points and assess one more point of PEN listed, and the PC is assessed one point for every five points the incoming round stops.

The problem is the old penetration figures. How to integrate them I know I'm not doing it the right way, but haven't put in the thought to fix it.

Is this a worthwhile idea Should I proceed with it further Does anyone else have any ideas on how this might be fixed

The relationship between Armor Values, Damage, and Penetration is ALWAYS the problem. Fix one...break another. It can get frustrating pretty fast.

It may sound funny, but I actually began using a system similar to what you propose for less-than-lethal damage in Twilight2000. I CANNOT EVEN REMOTELY CLAIM CREDIT FOR IT THOUGH. I "lifted" the Stun Damage system from Fantasy Hero for use in my game. I give each player a number of DAMAGE DICE (not points) equal to their HTH Damage Rating. This damage (using #D6 for punches, & #D10 for kicks) is all stun damage. Every 5 FULL POINTS OF STUN DAMAGE EQUAL 1 POINT OF WOUND DAMAGE to the location hit (figured from the damage rolled). Each location also has a "Stun Multiplier" (X1/2 for limbs, X1 for chest, X1.5 for abdomen, & X2 for head) to multiply the stun damage (only) and a player has five damage levels just like the Wound Thresholds.... Light, Medium, Serious, Critical and Deadly wound levels.
Those thresholds act like fatigue and a wound that exceeds your Deadly Stun Threshold renders you unconscious. I figure each Stun Damage Wound threshold by adding STR & CON. Thus a person with a STR of 5 and a CON of 5 would have a 10 Light Stun Level and a 50 Deadly Stun wound threshold.

I'll have to think about how you may improve your "Armor Ablation System()" for play. I'm not really sure what would work best right now.

[The Dark]

So I am a little confused, are you talking the NIJ ratings or the in game ratings I think that you are talking the NIJ ratings but even the best soft armor (NIJ 3A) will not stop any rifle round. Or at least out to 100 meters (that is as far as our range at work can shoot), at that distance our M4's go through both sides and the target dummy and into the back stop. Having gone to several body armor shoots from the industries professionals (AKA sales reps) where we got to shoot vests with all kinds of things, not a single vest stopped rifle rounds tell we got to the hard plates.

So I guess I am asking are you trying to get more realistic If so all rifles (not pistol caliber carbines) will penetrate them at just about any range that you can hit with, and even the rifle rated plates are only good for a limited number of hits (level III rated at six, level IV rated at one, but both last longer). Or are you trying to make it less lethal on the players

The problem is dealing with weapons at the high end of the pistol range and low end of the rifle range.

Using book values, the two .44 Magnum revolvers are both Dam 3, Pen 2-Nil. The M16A1 is Dam 2, Pen 1-Nil. AV 1 will be penetrated by both, AV 2 will be resisted by both.

Using Paul's damage values, the .44 Magnum is Dam 4, Pen 1-Nil, and the M16A1 is Dam 3, Pen 1-Nil, so it's impossible to protect against the .44 without also protecting against the M16 (the M4 is also 3, 1-Nil). You need AV 3 to protect against an M16 or M4, and AV 4 to protect against the .44 Magnum. Since NIJ Class IIIA is supposed to protect against .44 Magnum.


Going back to book values (and using the NIJ 0101.06 standard), each level needs to protect against the following:
IIA: 9mm, .40 S&W: no .40 S&W weapon is in IWW, and all the 9mm pistols are Pen Nil.
II: 9mm, .357 Magnum: .357 Magnum is Dam 2, Pen 1-Nil.
IIIA: .357 SIG, .44 Magnum: Only 9mm Sigs are included, but .44 Magnum is Dam 3, Pen 2-Nil.
III: 7.62x51mm: Every rifle in IWW using 7.62mmN is Dam 4, Pen 2-3-Nil.

Looking at it this way, it becomes clear that the damage and pen values are the problem. AV2 is the minimum to protect against .357 Magnum, but it also protects against 7.62x51mm and .44 Magnum.

If we use numbers from the weapons Paul has done up:
IIA: the .40S&W Glock 22/23 series are Dam 2, Pen 1-Nil
II: the S&W Model 13 (.357 Magnum) is Dam 3, Pen 1-Nil
IIIA: the S&W Model 29 (.44 Magnum) is Dam 4, Pen 1-Nil
III: the Springfield M14 is Dam 4, Pen 2-3-Nil

Paul's numbers would work if we change the Pen around. It doesn't really make sense that pistol rounds (slower and heavier) have better Pen, since velocity is what matters (as swag mentioned). If all the pistols mentioned become 2-Nil, and the M14 is 1-2-Nil, then we end up in a situation where AVs of 1 (for IIA), 1.5 (for II), 2 (for IIIA), and 4 (for III with plates) will work against the appropriate weapons. An M-16, with Dam 3 and Pen 1-Nil, will penetrate up to IIIA and be stopped by III. This is better, but it's not systematic yet.

The problem extends into Fire, Fusion & Steel, where low-powered rounds (between 600 and 2000 joules muzzle energy) are the best penetrators. Get a round up to 1990 joules (but don't go over 2000), and you'll get Dam 3, Pen 1-Nil; the next time something will be able to penetrate AV2 is at 6807 joules, when you get Dam 5 and Pen 2-3-4. The solution would be to rewrite the Penetration table so that each step is no worse than the step before. As it stands, there are two "bad" steps - going from 1-Nil to 2-Nil at 2000 joules, and from 2-3-Nil to 2-4-6 at 5000 joules. I don't have that solution yet (i.e. a rewritten Pen table for FF&S), but at least now the problem seems clear.

[The Dark]

A modest proposal regarding armor penetration

Following up from my last post, the biggest issue with having multiple types of armor is that the interaction of Dam and Pen stats gives no real range of plausible AVs, since the same AV2 armor is the minimum to protect against both a .357 Magnum and a 7.62x51mm shot. As such, here's my suggested change in Pen values for firearms:

If Pen WAS Nil, it now IS Nil
If Pen WAS 1-Nil, it now IS 2-Nil
If Pen WAS 2-Nil, it now IS 2-4-Nil
If Pen WAS 2-3-Nil, it now IS 2-4-6
If Pen WAS 2-4-6, it now IS 2-3-4
If Pen WAS 2-3-4, it now IS 2-2-3
If Pen WAS 2-2-3, it now IS 1-2-3

Damage dice may need to be adjusted slightly; I would change the M14 to Dam 5 so that it penetrates AV2 at close/medium and AV1 at long range with its new Pen 2-4-6. Meanwhile, the .357 Magnum can be stopped by AV1.5 and the .44 Magnum by AV2. Suggested AVs would be:
NIJ IIA: 1 (defeats the Dam 2, Pen 2-Nil pistol rounds)
NIJ II: 1.5 (defeats the Dam 3, Pen 2-Nil .357 Magnum)
NIJ IIIA: 2 (defeats the Dam 4, Pen 2-Nil .44 Magnum)
NIJ III: 2.5 (defeats the Dam 5, Pen 2-4-6 7.62x51mm)

Also, blunt trauma is suffered at a rate of 1 point per AV of damage prevented (minimum 1), rather than 1 for 1, so someone shot with a Dam 2, Pen 2-Nil pistol while wearing IIIA armor (AV2) takes 1 point of trauma damage, rather than 2.

Rounds known for armor penetration would subtract 1 from their Pen (so 2-Nil would become 1-Nil, 1-2-3 would become 1-1-2) and also subtract 1 from all damage dice. The P-90 (Dam 2, Pen 1-Nil on Paul's page) would be Dam 2, Pen 2-Nil under this system, but based on the 5.7mm being designed for penetration, it's modified to Dam 2-2, Pen 1-Nil.

This will still need some ironing out, I'm sure. The M16 is a clear problem, since it becomes Dam 3, Pen 2-Nil under this system, which is far too weak. Considering it AP lets it defeat NIJ III armor, which I'm not happy about, but the other solution is likely to up it to Dam 5, since it should be able to defeat NIJ IIIA. Maybe the trauma plates should add a full AV and NIJ III should be AV 3

[swaghauler]

The Dark:

NIJ Level 3 (Rifle): I wouldn't worry about 5.56mmN penetrating NIJ Level 3 (rifle) plates. Level 3 rifle plates (which are representative of SAPI plates too) are only rated for 7.62mm NATO rounds of 147grn weight at a velocity of 2780 fps. The 5.56mm NATO round has a velocity ranging from 2800 fps (M855) to 3100 fps (M193) and has ROUTINELY penetrated SAPI plates at short range. This is why my PEN numbers for an M16A2 (DAM 2D10/2D10/2D10/1D10) are 1/2/2/3. It can penetrate a SAPI plate in its older lead configuration (newer copper bullets seem to have trouble here).

NIJ Level 4/ESAPI standard plates: I haven't seen you post anything about NIJ Level 4/ESAPI plates so I thought I might mention them here. They are rated to stop at least a single 166grn 3006 Armor Piercing round at 2780 (today this round would be considered only an "enhanced penetrator" compared to the Tungsten and DU rounds in service now). It stops ALL 5.56mmN rounds as well as all 7.62mmN rounds.

NIJ Level #+ plates/inserts: Any vest you see that features a + after its rating is a vest NOT rated by the NIJ. The manufacturer of these vests Guarantees that it meets the level standard (ie Level2+, Level3+...the most common types) that precedes the + but is claiming that vest actually EXCEEDS that standard. The problem with this is it may JUST EXCEED the rating or it may be at virtually the next NIJ Level of protection. Since tests vary from manufacturer to manufacturer, you are basically "blind" as to the vest's true rating.

Pistols, Rifles, Soft, and Hard Armors:

If you keep having balance issues, you can try differentiating between Pistol Rounds and Rifle Rounds as well as between Soft Body armors (designed for pistols) and Hard Body armors. I would try designating DAM with a "P" for pistol or an "R" for rifle. You then give your armor a suffix of "S" for soft vests and "H" for hard plate armors. Anytime RIFLE DAMAGE encounters SOFT ARMOR, just divide the armor rating in half (rounding down) BEFORE accounting for PEN to reflect the superior penetration of rifles. This, of course, would NOT APPLY to Hard armors.

Finally, I would have any "Surplus Protection" of HARD PLATE ARMORS reduce the BLUNT TRAUMA DAMAGE by that amount. This reflects instances where soldiers wearing SAPI/ESAPI plates have been hit but are completely uninjured (especially by long range fire). Knockdown Dice would still apply (I apply Knockdown if you are hit by a round with MORE DAMAGE DICE than the average of your STR and AGL).