Lessons on Body Armor

A lot of non-gun folks don’t have a good understanding of body armor.  Too often you hear the term “bulletproof vest” bandied about, and that term is about the farthest from the truth as you can get.  There is no such thing as a bullet proof vest, only bullet resistant vests, and how much resistance you get depends on exactly what the vest is rated for.

An intrepid blogger actually did some real world experiments on this, to see what would penetrate and what wouldn’t.  The lowly .22 Magnum rimfire round fired from a rifle would seem to be enough to penetrate a level IIIA vest, which is considered sufficient to stop a .44 Magnum.  This seems surprising, but not really; penetration is always a matter of being small and fast.  I would like to see data on some other “pistol” rounds fired from rifles, to see what would happen there.  What about some of these hot small bore rimfire rounds like .17 HMR or .17 HM2?

Kevlar vests have been a lifesaver for law enforcement, but they aren’t magic.  They defend against the kind of threats cops are likely to encounter, but it’s important for folks to have an understanding of the technology, and its limitations.

8 thoughts on “Lessons on Body Armor”

  1. I read the test results and the one big mistake he made was saying the .223 Rem. round is the same as the 5.56 NATO round. It is not. As I said in the reply I posted there, the 5.56 NATO round contains more powder and produces upwards of 10,000 psi chamber pressure and will likely blow out the breech of a rifle made to fire .223 Rem. rounds only. The case dimensions of the 5.56 NATO rounds are also not the same. The neck is slightly longer and will not fit a .223 Rem. rifle properly. You can shoot .223 Rem. rounds safely from a rifle chambered for 5.56 NATO, but not the other way around, so please don’t anyone try to.

  2. Sorry, I meant to say “…upwards of 10,000 more psi chamber pressure than a .223 Rem. cartridge.”

  3. It’s good advice. You can definitely hear the difference between 5.56x45mm NATO spec rounds and standard .223 rounds. And if you can hear the difference, you can definitely bet there is a difference.

  4. RedneckInNY,

    Yes, 5.56 is loaded hotter. But saying that it will blow out a rifle chambered for 223 is nothing short of hogwash! It is not the hotter load which causes the problem.

    At issue is the length of the leade on the chamber. 5.56 has an unusually long throat to accomodate certain very long tracer rounds. 223 has a much shorter leade.

    So shooting a 5.56 tracer will indeed cause overpressure in a .223 chamber reamed to SAMMI minimum specs.

    But a .223 round loaded with a long bullet and a steep ogive (like some of the very heavy .223 match bullets) can also cause overpressure when fired in a 223 chamber reamed to SAMMI minimums. SAMMI minimums where written when a 90 grn .223 was unheard of.

    This is why reloading manuals always talk about being aware of where the bearing surface of the bullet is with respect to the lands.

    Of course most chambers (.223 and 5.56) are reamed with very long throats to avoid these problems. Liability is the reason why.

    The flip side is when you get a custom barrel made you can get the chamber reamed for the OAL and bullet you will be using to avoid the huge gap from the lands you get.

    There is a huge amount of hogwash out there on .223 vs 5.56 and .308 vs 7.62.

  5. The .22 magnum is apparently a very penetrative round. I belong to an indoor pistol range and all calibers up to .44 magnum are allowed. The one that is strictly verboten is the .22 magnum because, I am told, it will punch holes in the steel backstop and bullet trap. If the antis find this out I guess the 22. magnum will be labeled as a “cop killer bullet.”

  6. This is good information…one of my back up defensive guns is a Heritage Arms single action chambered in .22 mag (I live alone and have a number of hidden revolvers strategically placed throughout my apartment). My “main” defensive revolvers are in .357 mag, if I don’t have time to load my Mossberg 12 ga. under my bed, that is.

    I do have a few semiautos for carry pieces but I don’t like to keep the magazines loaded for months on end, whereas I don’t mind keeping the revolvers loaded continuously.

  7. I was going to shoot the .22 long rifle at it just for the purposes of the test but I fired the .22 Mag first. I stuck my hand inside the vest and didn’t feel that it had penetrated so I said there was no way the .22 LR would go thru if the .22 Mag didn’t. It was later that I saw the shot hole where it went thru.

    I knew that .223 and 5.56mm were different and that the chamber was cut different, but the rifle had .556mm/.223 Rem stamped on the side so I figure the chamber is .556 and that .223 can be fired safely in it. I had no doubt that the round would go thru the vest but it helps to demonstrate anyways.

    I’m thinking about another round of tests sometime in the summer. Thanks for linking!

  8. As to pistol rounds beware of the 7.62×25, most commonly found in Tok’s and CZ52’s. That round smokes and penetrates extremely well. Check out some of the tests on http://www.theboxotruth.com. Old Painless shot a kevlar helmet with a mess of pistol rounds and the only one to penetrate was the 7.62×25 (of course, all centerfire rifle rounds tested blasted right on through).

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