Does anyone know the law regarding armor peircing bullets? Are they legal or illegal?

Illegal (See ATF info).

The ATF does not consider M855/SS109 to be armor piercing ammo (check state laws though, they may be different, apparently Illinois outlaws M855)

<ATF Quote from website above>
NOTE: THE FOLLOWING CARTRIDGES HAVE BEEN REMOVED FROM THE DEFINITION OF ARMOR PIERCING AMMUNITION:

bullet 5.56MM (.223) SS109 and M855 Ammunition, Identified by a green coating on the projectile tip.

bullet U.S. .30-06 M2 AP, Identified by a black coating on the projectile tip.
<ATF Quote from website above>

See also the Ammo Oracle

Iam talking about armor peircing projectiles used for reloading not assembled ammunition.