What is Armor Piercing Ammunition?

    An AR500 level III steel armor plate.

    That seems like a pretty straightforward question, doesn’t it? On the surface, armor piercing ammunition ought to be ammunition that pierces armor, right? Seems pretty simple. Except it isn’t. At least, not according to the BATFE. Under 18 United States code, AP ammo is defined rather arbitrarily as:

    (i) a projectile or projectile core which may be used in a handgun and which is constructed entirely (excluding the presence of traces of other substances) from one or a combination of tungsten alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium; or

    (ii) a full jacketed projectile larger than .22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile.

    Steel core Norinco 7.62x39mm 123 gr FMJ

    And that’s why Norinco steel core 7.62x39mm ammunition was banned from import back in the 90’s, which makes perfect sense because everybody knows that 7.62x39mm is pistol ammo. Wait, is it? According to the federal government, yes. Because handguns exist that will fire it, the BATFE has determined that 7.62x39mm is pistol ammunition. Okay, so it’s kind of goofy to call it pistol ammo, but it is armor piercing, right? After all, it has a steel core.

    Wait, so that has to be some really tough armor though, right? Not really. The lightweight polyethylene armor that we used in this test is nowhere near as tough as most other rifle armor. In fact, this steel core ammunition won’t penetrate any armor that is designed to stop rifle rounds. Why not? The feds say that a steel core makes ammunition armor piercing. The steel core in this ammo is very soft steel and it is only used because it was cheaper than lead. Of course, it will easily perforate soft armor. But that is only intended to stop handgun rounds. Any rifle ammunition will do that. So rifle ammunition that can’t actually penetrate rifle armor, is defined by the federal government as armor piercing pistol ammunition. What about pistol ammunition that does penetrate pistol rated armor? Like this Lehigh 10mm? Is this AP ammo?

    Soft armor panels

    Nope. Not AP. Okay, so this actually is pistol ammo and it did zip right through that level IIIA vest like it wasn’t there. This may give you Forest Whitaker eye to consider, but that is actually not AP ammo. Although it is made entirely of copper, it isn’t beryllium copper, as specified by the statute. It doesn’t meet any of the standards listed above so it cannot be classified as armor piercing ammunition, regardless of how well it pierces armor. But, if I may channel Billy Mays, wait there’s more!

    You may recall that the BATFE tried to classify M855/SS109 as armor piercing not too long ago.The justification was a very creative interpretation of the federal statute listed above. Since AR-15 pistols are rather common, they pulled the same trick as with the Norinco stuff and called .223 Rem and 5.56x45mm “pistol ammunition”. M855 does indeed have a steel component in its core, and it is quite a bit harder than the steel used in Norinco 7.62x39mm. But it is hardly “constructed entirely” of steel, as the statute reads. To interpret the statute that way, you would have to define the penetrator (about 1/6 the weight of the projectile) as being the entire “core” and completely disregard the existence of the lead core out of hand. That’s been covered numerous times in other articles and, spoiler: they gave up and stopped trying to take a mediocre 5.56mm load off the market.

    Lake City M855 5.56x45mm FMJ

    What’s particularly ironic is that, while M855 is not armor piercing ammunition by federal statute, it actually is capable of piercing the very same armor plate that the Norinco 7.62x39mm could not perforate.
    I know that this is rather convoluted and it doesn’t get any less so.There are virtually endless variations on this theme. Plain old lead core 55 gr M193 5.56mm (also not AP by federal statute) can generally perforate steel level III plates, while M855 is easily stopped. That’s because, when it comes to steel armor, velocity matters quite a bit more than bullet construction.

    Then there is the military definition of “armor piercing” which is pretty much any ammunition designed to meet a standard in perforating a particular type of armor at a specified distance. Some level III+ steel plates can stop P60 or P80 7.62x51mm, which are actual, military AP ammo type classifications but

    M80A1 7.62x51mm Enhanced Performance Round

    M855A1 EPR or M80A1 EPR, which are not AP (according to DoD or federal statute) can cut through it like it’s not there. And, of course, the NIJ level IV standard is defined by the ability to stop .30-06 M2AP, which was not only designated by the military as armor piercing, but also meets the federal definition . This projectile was widely used during WWII. It was actually issued exclusive of M2 ball for much of the war because it was relatively cheap, highly penetrative, and had great terminal effect, so there was little advantage in complicating the supply chain with two different types of ammunition. There are multitudes of anecdotal reports of Joes preferring M2AP and extolling its virtues in digging through trees and other obstacles to root out the Jerrys.

    Come And Take It NIJ level IV stand alone armor plate

    The fun part about that is that many of the ammunition types that the military classifies as AP would actually meet the federal statute, if the BATFE were inclined to classify them as being intended for use handguns. Somehow, I don’t think that the preposterous nature of a .30-06 pistol would bother the BATFE.

    The takeaway is that, just as there is no such thing as a “bulletproof vest,” there is also no such thing as “armor piercing” ammo. At least insofar as there is always something that can stop it. If wearing armor is part of your job, it is strongly recommended that you learn the limits of your gear. Likewise, if you rely on a firearm for defense, it is wise to know what it can do against barriers and body armor.

    Andrew is a combat veteran of OEF and has performed hundreds of ballistic tests for his YouTube channel, The Chopping Block (https://www.youtube.com/user/chopinbloc). He is an avid firearm collector and competitor and lives with his family in Arizona. If you have any questions, you may email him at [email protected]