FEDERAL CARTRIDGE CO
5.56 NATO, SS109 Steel Core (Penetrator) Full Metal Jacket Boat Tail (FMJBT) Bullet, 62 Grain, Green Tipped, 3025 fps, 420 Rd/can
The two most common 5.56 rounds are the 55gr M193 and the 62gr “green tip” M855, both of which are used by the US military. Both are FMJBT (Full Metal Jacket Boat-Tail) designs with a cannelure that are capable of reliable, severe fragmentation when they are moving at speeds over 2700fps (and fragments to a lesser degree all the way down to 2500fps). This occurs as the projectile hits soft tissue and the bullet begins to yaw. As this happens, the bullet will often break apart at the cannelure due to the stress and separate creating a devastating wound channel. The US made M855 is painted with a green tip to distinguish it from M193, so that troops do not shoot M855 in their 1 turn every 12 inch twist barreled M16's that would fail to properly stabilize the heavier and much longer bullet (length being a primary factor in bullet stabilization). The NATO SS109 62gr steel core “penetrator” bullet is used in the M855 round. The steel penetrator makes it more effective at penetrating hard targets and such. Because of the steel core (steel is lighter than lead), the SS109 bullet is actually longer than a completely lead core 62gr bullet would be.
The Federal XM855 are production overruns or in some cases "seconds", which may have been declared as such due to a small sampling not passing military specifications in one way or another. It is loaded to NATO specs and is NOT intended for use in commercial or bolt-action rifles chambered in 223 Remington, but is perfect for your AR15 in 5.56 cal. Each round is brass-cased, boxer-primed, non-corrosive, and reloadable. It is both economical and precision manufactured in the United States. Shipped in a 30 caliber military ammo can.
Manufacturer: FEDERAL CARTRIDGE CO
Model Number: XM855FAC1
Caliber: 5.56 NATO
Bullet Type: Full Metal Jacket Boat Tail (FMJBT)
Bullet Weight: 62 GR
Muzzle Energy: 1260 ft lbs
Muzzle Velocity: 3025 fps
Rounds-box: 420 Rounds Per Can
NOTICE: While the 5.56x45mm NATO will fit in a .223 Remington chamber, the 5.56 is a military round that runs at higher pressures than its .223 counterpart and is not recommended to be fired in a .223 Remington chamber.