For one thing, we can almost certainly assume that by "armor piercing," Rep. Speier means that the ammunition is capable of defeating soft body armor, like that worn by cops on the beat, rather than the much heavier and bulkier rigid body armor worn by combat troops and S.W.A.T. team personnel. To be considered "armor piercing," in other words, the ammunition would need only, at most, to defeat Level IIIa armor (if Speier lowers the standard below that, even more ammunition would be banned). In fact, Speier makes that pretty clear in her press release, which talks about "first responders," rather than soldiers:

http://www.examiner.com/article/new-armor-piercing-ammo-legislation...