[Skywise]

And can be sold to civilians?

[Jewbacca]

The term “armor-piercing ammunition” means:

(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.

Perhaps he sold pistol ammo that was not used?

[Blood of Tyrants]

Yep. M855 ammo is technically not AP. Instead it is determined to have “enhanced penetration”. Legally only AP designed for use in handguns is outlawed. But the ATF has ruled that if ANY handgun can accept a round designed for a rifle, it is a handgun round. The exception is that it is still legal to sell .30-06 AP surplus.