Tracer, SFAIK is plenty legal.
Now. Sit down. Get a firm grip on unreality: Remember those non-existent "Cop Killer" bullets? So the feds passed a law saying you can't have 'em? Hokay. With such things as the Contender having a barrel for a .308, ATF jumped up and began shrieking that this meant that the .308 was a pistol round, and AP is bad, bad, bad because it's an evil cop-killer bullet.
Which is a long-winded way of saying that AP in any rifle cartridge but the .308.
Your federal government is protecting you as efficiently as it did at the WTC.
Art