What about the .308 bullets with the steel penetrator (black tip)?
I thought it was pretty evident that .308 bullets were not 'handgun' bullets.
In early 1994, the BATFE reclassified .223, 7.62x39mm, and .308/7.62x51mm as handgun rounds for the purposes of the 1986 law. The justification was the production of some Olympic Arms AR-based pistols in .223 and 7.62x39, and I have no idea why .308 was included. The justification may be that AP in these calibers may allow them to penetrate Level III body armor, which would otherwise be proof against those calibers. AP is irrelevant in larger calibers (.30-06 and up) because they will go through Level III armor even with non-AP bullets, so banning AP in .338 WinMag is pointless.
So the upshot is that all handgun calibers, as well as .223, 7.62x39mm, and .308/7.62x51mm, fall under a construction-based AP ban, but larger rifle calibers do not. You can shoot solid steel match bullets in a larger caliber, but steel-core 7.62x39mm is prohibited.
Back to components. If you possess .308-diameter AP bullets that you intend to reload into .300 WinMag ammo, or .30-06, I don't
think that would be illegal (though I'm not a lawyer). But possession with the intent to make .308 Winchester/7.62x51mm AP could possibly be a crime, and construction of such ammo definitely would be.
Where 'armor' is being described here, it is hard armor, not soft. Soft armor is readily penetrated by pointy military ball ammo fired from a rifle and similar pointy ammo such as the 5.7 pistol ammo. Just because it can penetrate soft armor does not then make it classified as armor piercing.
Doesn't have to be pointy if it's traveling at rifle velocities. Round-nose .30-30 Winchester softpoints will easily penetrate NIJ Level IIIA armor, which is why Ted Kennedy said in 2004 that .30-30 Winchester ammo needs to be banned.
With civilian-legal ammo, 5.7x28mm will not penetrate any vest that is proof against a .357 magnum 125-gr JHP, as I recall. The Bradyite video alleging armor penetration by civvie 5.7x28mm showed an old NIJ Level
IIA vest being perforated, which is not even rated to stop .357. NIJ Level IIIA will stop all 5.7x28mm except the military-only tungsten-core stuff, and NIJ Level II will stop any load currently marketed in that caliber, IIRC.