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> Armor's mostly useless without Bod to back it up, Are house rules common?
Austere Emancipa...
post Jul 15 2004, 03:48 PM
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I found a lot of mentions of critical injuries caused by shotguns on police officers wearing armor, too, but those resulted similarly from damage to unprotected areas, mainly the throat and face.
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hyzmarca
post Jul 15 2004, 06:27 PM
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QUOTE (Austere Emancipator @ Jul 15 2004, 10:18 AM)
12G 2-3/4" 1oz slug:
18.5mm diameter 437gr 1500fps, 2185 ft-lbs, ~8.13 ft-lbs/mm^2

.44 Magnum SWC:
10.9mm diameter 240gr 1450fps, 1120 ft-lbs, ~12 ft-lbs/mm^2

The .44 Magnum puts almost 50% more energy per unit of area -- which is a rather decent indicator of armor penetration when projectile construction is similar. Compared to a lead slug with a very blunt head, I'd assume the .44 Magnum would penetrate flexible body armor better or at least as well. The "SMG 9mm" which NIJ level IIIA is tested against puts ~8.46 ft-lbs/mm^2 and is an FMJ ogive.

On the other hand, I assume you can get 1oz 12G slugs to muzzle velocities well beyond 1700fps, especially the 3-½"s. At 1800fps (~3146 ft-lbs, still only ~11.7 ft-lbs/mm^2), I doubt any wearable flexible west could reliably beat the NIJ backface deformation criteria, so rating any flexible vest against 12G slugs is meaningless.

[Edit]Just realized what an abomination the unit "foot-pounds per square millimeter" is, and how I should have either used inches or Joules instead. Can't be bothered to go back and change the values. Anyway, the units aren't important because the point is to compare the values.[/Edit]

Well, the page I linked too states that an officer was killed when a 12 guage slug drove pieces of his vest into his abdomen. That suggests that it didn't actualy penetrate, but it deformed the vest with so much force that pieces of kevlar tore off and penetrated the officer's abdomen.

QUOTE
A North Carolina police officer was killed recently when he was struck by a shotgun slug that drove pieces of his conventional bullet-proof vest into his abdomen. The officer might be alive today had he been wearing a vest with the materal developed by Thomas.


http://www.radix.net/~jchang/armorfaq1.txt

According to this FAQ, level III is rated to stop 12 guage rifled slugs, but IIIA is not.
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GrinderTheTroll
post Jul 15 2004, 06:28 PM
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We have a Sam who is incredibly fast, but only has a 4 body. His MO is to strike first, else he sometimes get creamed. It was a trade off sacrificing it all for some hot cyberware and I make him think twice about what he does with his movement. It's balance well enough that he knows better than to run out into a hot-lead bath, that's reserved for the real meatshields.
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Siege
post Jul 15 2004, 06:35 PM
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I've read some accounts that a bullet-proof vest actually makes wounds from high-powered rifles worse because of the spintering effect on the bullet, resulting in an impromptu shrapnel affect.

I think they were discussing Class 2 vests though.

-Siege
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Austere Emancipa...
post Jul 15 2004, 06:36 PM
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I couldn't open the site at first, and it's really slow even now. It has some interesting tidbits...
QUOTE (http://www.univrel.auburn.edu/multimedia/publications/LAweb/thomas.html)
Thomas' work has advanced quickly to the point where his improved material can stop armor-piercing bullets and even a 12-gauge shotgun slug.
Indicates that whoever wrote the article doesn't know what types of projectile threats penetrate body armor the best. 12G slugs penetrate far worse than even 7.62x51mm FMJs, let alone armor-piercing bullets.

That vest being torn apart thing sounds really silly somehow. When you look at pictures of penetrated flexible body armor panels, there's always just the one hole where all the strands have snapped. I do not doubt that the blunt trauma from being hit by a shot slug to many flexible body armor vests could be very dangerous and even fatal, however.
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Austere Emancipa...
post Jul 15 2004, 06:47 PM
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The full deal about NIJ classifications can be found here. No, level IIIA vests are definitely not guaranteed to stop 12G slugs within the backface deformation criteria. I do hope I didn't come off like I was trying to say that they are. I was simply wondering about exactly how well shotgun slugs fare against flexible body armor. Obviously they fare extremely badly against any rigid body armor...

QUOTE (Siege)
I've read some accounts that a bullet-proof vest actually makes wounds from high-powered rifles worse because of the spintering effect on the bullet, resulting in an impromptu shrapnel affect.

I think they were discussing Class 2 vests though.

Would not surprise me. The same principle at work that makes a .340Wby 225grain Soft Point a rather bad performer against big, tough game at short distances, but allows the same loading to totally fuck up the human thorax. I dare not say much more about this, because there's simply too much physics at work there for me to say anything smart.

When facing 5.56x45mm M855 FMJs, you might pray for even a measly leve II vest, to slow the bullet down enough to stop it from fragmenting. But if you were being shot at with 7mm RemMag solids, you might be better off without any armor than with that level II. Etc etc.
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