Ballistic Protection standards reference

[The Dark]

Originally Posted by 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).

I couldn't remember how 5.56mmN did against NIJ III, but based on your post and a comment on an armor manufacturer's site, I think the M193 round should definitely be Dam 3-3 Pen 1-Nil. I'm still not sure about the SS-109, which isn't quite as good a penetrator. It's better than a pure lead core, but it's not up to the same level as the M193 - SAPI plus an Interceptor vest has to survive three Green Tip strikes in order to meet the standard (along with three 7.62x39mm and three 7.62x54mmR).

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 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.

I hadn't gotten to that one yet, since I wanted to make sure I had the II and III balanced before moving on to the IV. Since an armor-piercing .30-06 round should be Dam 4-4, AP 1-2-Nil, AV4 would suffice. As a side note, NIJ IV is rated to stop at least one round. The manufacturer can tell the lab to fire up to six shots at each panel, which is why their required number of armors for testing is wildly variable, from 7 to 37, since the test requires 36 shots, which could be on 6 armors or 36 armors, depending on the manufacturer's specifications (1 armor is a spare). However, without knowing a specific manufacturer's direction to the test lab, NIJ IV has no requirement above that one shot. ESAPI requires three shots from 5.56mmN, 7.62x39mm, 7.62x54mm, and .30-06AP, though for the last round only the first two shots are counted for pass/fail.

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.

A + is supposed to indicate that an armor has been tested to that level, and against an additional type of bullet as well, although I'm not sure how well that's enforced (and since only five labs are NIJ-certified, they'd be very busy with all the armor types being promoted these days). The NIJ test has allowances for non-standard armor (in the 0101.06 procedure, it's section 2.6 and Appendix B). Appendix B also has rounds that are "special threat rounds" that are considered "of particular concern to law enforcement," which could probably be considered AP rounds for the purpose of these rules.

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.

I think the adjusted Pen stats, plus shifting armor to be 1 (for IIA) to 4 (for IV) solves the problem for most rounds. I do still need to look at some of the newer rounds (like 6.5mm Grendel or 6.8mm Remington SPC) to determine if they're more like the >7mm "brute force" rounds or the <6mm AP rounds. Since pistols are pretty much all 2-Nil, and the exceptions are relatively weak (the Five-seveN, for example), the only real trick is balancing out the rifles.

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).

Yes, I agree that the plates should reduce blunt trauma damage. I even think the heavy soft armors should have some reduction:

SOFT armor: Divide number of dice of damage stopped by AV and round up; this is the blunt trauma damage taken.
HARD armor: Divide number of dice of damage stopped by AV and round down. Subtract any excess AV. This is the blunt trauma damage taken.

Examples using a close-range .44 Magnum (Dam 4, Pen 2-Nil):
Against IIA, 2 points of damage are absorbed. Target takes 2d6 and 2 blunt trauma
Against IIIA, all damage is absorbed. The 4 dice are divided by 2 (the AV), and the target takes 2 blunt trauma
Against III, all damage is absorbed. The 4 dice are divided by 2.5, giving 1.6, rounded DOWN to 1. The armor can absorb 5 dice, so an extra point is subtracted, and the target takes no damage.

Other things to keep in mind with this system - armor only protects where it covers; for most modern armors, that's the chest and abdomen, with maybe a 50% arm coverage. That still leaves a target with 40% uncovered on the legs, either 10 or 20% uncovered on the arms, and (probably) 3.3% uncovered on the head. At best, armor will protect against slightly less than half of random hits. Also, Outstanding Success will allow penetration of armors that would normally protect (an Outstanding Success by the .44 Magnum against NIJ III would cause 3d6 damage and 2 blunt trauma).