3000fps out of the muzzle of an AR sounds super-scary to me. Not saying it's not true, but man, that's pushing things isn't it?
3000 FPS muzzle velocities aren't uncommon with 5.56 chamberings. M855 clones are in the 3100 FPS range from a 20" BBL and M193 clones are actually in the 3200 FPS range from a 20" BBL. The heavier stuff, such as MK262 is down in the 2600-2700 FPS range, however.