New body armor options for soldiers

[Anthony]

Originally Posted by Crakkerjakk

Well, if Anthony is right that the total surface area of the plates are half of the torso

No, it's slightly under 1/2 of what GURPS calls the 'torso' location. It's about 1/3 of the total area of the torso (total torso area is ~7 square feet). The thing is, much of the missing coverage is area that is unlikely to get hit if you're being attacked from the front or back and have partial cover -- it's area below the waist or that are much more likely to be hit from the top or sides than the front.

[Fred Brackin]

Originally Posted by General Lee

AFAIK, some police officers from SWAT teams have died from shots that came under the armpit. Some might say that is because of barricated situations, .

I knowm of one specific case. It was before te main Internet era so searching "Digristi9ne" may not turn up much.

The officer was going down the hall of a residence and was probably turned sideways (though still in a firing position for his SMG). A single 25 ACP entered from the side and hit his heart. Exactly which HT roll he failed may depend on how you interpret his final burst of SMG fire.

I think this hallway situation may be a common problem. this may be be from conversations/playtesting with Lisa for Cops or SWAT.

[General Lee]

Take a look a this:

Front and back SAPI plates:
Extra Small - 1.27 kg (2.8 lb) | 184 x 292 mm (7¼ x 11½ in)
Small - 1.59 kg (3.5 lb) | 222 x 298 mm (8¾ x 11¾ in)
Medium - 1.82 kg (4.0 lb) | 241 x 318 mm (9½ x 12½ in)
Large - 2.09 kg (4.6 lb) | 260 x 337 mm (10⅛ x 13¼ in)
Extra Large 2.40 kg (5.3 lb) | 280 x 356 mm (11 x 14 in)
ESAPI plates are the same size but slightly greater in weight.
Extra Small - 1.70 kg (3.75 lb)
Small - 2.08 kg (4.60 lb)
Medium - 2.50 kg (5.50 lb)
Large - 2.85 kg (6.30 lb)
Extra Large - 3.25 kg (7.20 lb)

I google it and that came up. So, this is representative for what is encontered in field?

[safisher]

Originally Posted by General Lee

Take a look a this

Those are nice figures, but I should caution you that they don't necessarily immediately translate into something useful for GURPS. Here's why:

1. You'd need to take an average to find the average weight of the plate and then determine what is the average size for the operators they are fitting it. Is ST12 average or large size plate? What about ST9? ST14? Generally, GURPS armor has never bothered with size. You can decide on this, but just beware that this is not a transparent step. You must decide.

2. Then you need to consider that armor in GURPS has never mapped to the drawings which depict the hit locations very well. In other words, as well-meaning as the discussion on percentage of body covered is, if you go back through previous editions, those coverages were never very consistent and never really mapped to a given armor piece very well either. It's always been very abstract. There is a good reason for that -- abstract is simple, and simple is quick. Quick is usually more fun.

3. The suggestion to use a N/6 chance is a nice optional rule but requires an additional roll for every single attack. That's a lot of imposed record keeping for very little extra gain. I have also read where the sizes of plates and vests were determined to be the size necessary to catch most attacks they were intended to defend against. So do hits that bypass armor represent a normal hit, or a critical hit? If they are a normal hit that rolls normal damage and goes through is that armor failure? If its a critical hit then why roll every time to see if it bypasses armor? You can be a masochist and try to determine the actual figures, or something like them, but since we don't know where a hit falls on a location anyway (edge? center? somewhere between edge and center?) it's rather moot.

You all should feel free to play and decide as you like. I just wanted to pitch in here and say that there are some decisions that must be made and they are game play/design decisions which have ramifications, and contrary to what some may argue it is not just research on actual/historical weights and sizes and so forth.

[fredtheobviouspseudonym]

Just give the shooter an effective +1 to hit (vs. the maximum penalty on hitting for a prone target.) If you can't get sufficiently low (due to incompressible armor, full magazine pouches, or even while shooting with a long magazine [an actual issue with the M-16 in Vietnam] you're easier to hit.)

"Willie, I can't get any lower. My buttons are in the way." -- Bill Mauldin

[Polydamas]

Originally Posted by Anthony

No, it's slightly under 1/2 of what GURPS calls the 'torso' location. It's about 1/3 of the total area of the torso (total torso area is ~7 square feet). The thing is, much of the missing coverage is area that is unlikely to get hit if you're being attacked from the front or back and have partial cover -- it's area below the waist or that are much more likely to be hit from the top or sides than the front.

The GURPS cover rules already cover that to a certain extent. A GM can say "your Abdomen is behind cover" just like they can say "your right Arm is behind cover." I still think that TAANSTAFL is the simplest approach ("if it weighs half as much, it protects half the time"), because there are lots of similar issues with hand weapons (eg. shoulder armour and a helmet with brim will stop a high percentage of swings to the torso) but I will let the people here who know modern body armour suggest what chance of protection American body armour should provide.

[Crakkerjakk]

Originally Posted by safisher

3. The suggestion to use a N/6 chance is a nice optional rule but requires an additional roll for every single attack. That's a lot of imposed record keeping for very little extra gain. I have also read where the sizes of plates and vests were determined to be the size necessary to catch most attacks they were intended to defend against. So do hits that bypass armor represent a normal hit, or a critical hit? If they are a normal hit that rolls normal damage and goes through is that armor failure? If its a critical hit then why roll every time to see if it bypasses armor? You can be a masochist and try to determine the actual figures, or something like them, but since we don't know where a hit falls on a location anyway (edge? center? somewhere between edge and center?) it's rather moot.

I agree it's too much work to do manually. But it'd be relatively easy to program into a smartphone ap. I've already got a rough outline built in C++, just need to verify the percentages are right from back when I built it and port it over so you hit a button and it displays a location. I'm including everything from LT and MA.

Just need to actually get around to doing the java bit. Which has taken six months so far. :)

[safisher]

Originally Posted by Crakkerjakk

I agree it's too much work to do manually.

I've used the N/6 rules before, and they are okay when everyone is shooting single or semi-auto. But they are a real pain with full-auto, and shotgun fire is also a bit problematic. It's very much the same thing with trying to figure out gaps in armor from different stances or directions. "He's shooting Weaver, so he's got 3 in 6 on his body armor. Fool! Isosceles gives 4 in 6." or "I wait till he walks by and then shoot him in the side because everyone knows that vests don't protect from the side." It's simpler and quicker to just roll and deal with this stuff as critical hits. No one is required to do that, of course, but it's certainly the default assumption.

[Anthony]

GURPS seems to deliberately ignore armor coverage -- virtually no armor has the same resistance to penetration over its entire area.

[sir_pudding]

Originally Posted by Anthony

GURPS seems to deliberately ignore armor coverage -- virtually no armor has the same resistance to penetration over its entire area.

Isn't that the why damage is a variable roll and DR is based on average damage?