This is an exact replica of 5.56x45 MK 262 ammunition.  Sierra Match OTM projectile, velocities of 2760-2780fps.   Price is for a box of 100.
 
Loaded with new, annealed Nato stamped mil brass & CCI 400 primers.   This ammo has been extensively tested through 18" barrels and matches the velocity of mil 77gn OTM ammuntition.  Average 2760FPS.