XM ammunition is Metric caliber ammo that is contract overrun material. It may not meet all of the Mil-Spec requirements, however, it does meet all requirements of commercial amunition for pressure, form, fit and function.

Caliber: 223 Remington/5.56 NATO

Bullet Type: Boat Tail Metal Case

Bullet Weight: 55 GR

Muzzle Energy: 1270 ft lbs

Muzzle Velocity: 3250 fps

Rounds Per Box: 20

Boxes Per Case: 25

Casing Material: Brass