Modern Body Armor

[Icelander]

Originally Posted by Anthony

Both coverage estimates are likely high. Total torso area for an average adult male is somewhat over 7 square feet, of which maybe five is what GURPS would call 'body'. Those inserts are around 0.8 square feet, or about 1/6 each.

Fortunately for body armor, a lot of that is on the sides or top, frontal cross-section is probably only a third of that, giving 3/6 coverage. Also, the missing area is mostly around the edges so center shooting will disproportionately hit the plate. I would still be dubious about calling it more than 4/6.

Note that the vest covers Chest (9-10), not Torso (9-11). And while I agree that ballistic panels rarely cover more than a third of the torso, they generally cover most of the areas likely to be struck that count as the Chest hit location.

The 1/6 part of the Arm hit location that is armoured as the Shoulder in Low-Tech pretty much has to include some of the torso area around the shoulder, if we want to represent real world armour pieces. Neither shooter cut plates nor typical ballistic panels cover the shoulders or the area of torso close to them, but I'd argue that hits there mostly count as Arm hits anyway.

There are certainly vests that rate only 4/6 protection, even from the front, but given that 10 " x 12" is actually considered fairly decent coverage for an average male, I'm concerned that we would lack granularity to plausibly model the choice of smaller plates if we made the larger ones so unlikely to protect.

Originally Posted by Anthony

It's worse from the sides because (a) most of the armor isn't there, and (b) what armor actually is there is at the edges. I wouldn't give the sides better than 2/6.

That might be accurate, but on the other hand, even if shots come from the side hexes, it will be relatively rare for the character taking fire to be exactly aligned. A significant number of attacks from side hexes will still hit the front or rear of the Chest hit location.

Edit: That being said, I'm definitely looking to benchmark coverage of real-world vests with ballistic panels of various sizes as well as rigid plates. The n/6 system is intended to represent the odds of protecting against a typical threat, not the percentage of actual coverage, so even 'complete' coverage for the purposes of GURPS rules might not actually be complete 100% coverage in square inches, as the Armor Gaps, Chinks in Armor and critical hit results that bypass armor represent less than 100% coverage in cases where the armour will still protect most of the time, i.e. significantly more than 5/6 chance.

I'd like to hear the views of forumites as to what constitutes 'full' coverage of the Chest hit location with modern body armor (or if it exists commercially), what are typical 5/6 models, 4/6 and if any types of commercial body armour should rate only 3/6 or less protection of the Chest, i.e. less than 50% odds of a shot to center mass from the front actually hits the ballistic panels of the armor.

In principle, I have no objection to a fairly basic setup like the Protech TAC PR with 10" x 12" plates giving only 4/6 protection from the front and rear hexes, 2/6 protection from the sides. I just want to make sure that there is a sensible progression of levels of coverage, using what granularity the n/6 system affords, and that body armor which is widely issued is at least somewhat effective, even if less effective than if it had unrealistic 100% odds of protecting despite limited coverage.