T110's Northern Migration

The_Chieftain:   Well, is it a good place to start because it sounds all scientificky, or because it actually makes sense?   Here are a couple of examples. Norinco 7.62x39 (Standard AK-47/SKS thing) uses a soft steel core because it's cheaper than lead. It will not penetrate Level IIIA body armor. It is banned. M855 Ball 5.56mm was nearly banned about two years ago (i.e. the common milspec ball ammo, I've lots of it myself as it's cheap) because it has a steel exterior and lead core, and someone in ATF figured out that AR pistols existed. This was fought out, ATF reversed themselves, so it is not AP ammo per ATF. It actually will penetrate level IIIA body armor. M855 will not penetrate steel plate that the old M193 will penetrate, but M193 is not composite to fall under the prohibitions. M193 will not penetrate level IIIA, as the compositions of the two rounds react differently to the different targets. Similarly, some 10mm handgun ammo will go through level IIIA, but since the copper type is not listed in the statute, it's not armor piercing. You start to get the idea.   If you want to define something as 'armor piercing', set a standard type of armor, reasonable for the calibre. Anything short of frangible ammunition will go through a kevlar 'bullet proof vest' if fired from a .30-06, for example.