500 rounds PMC® (5.56x45) 55 Grain FMJ-BT Ammo.
Made to highest industry and military specs. Precision-made cartridges. Brass-cased, 55 Grain FMJ-BT bullet. Non-corrosive, Boxer-primed, reloadable, non-corrosive. Muzzle Velocity: 3,270 F.P.S. Muzzle Energy: 1,306 ft.-lbs.
Note: 5.56x45 and .223 are interchangeable, but the 5.56 military rd. runs at a higher pressure.