This is .223 Federal American Eagle 55gr. Full Metal Jacket Boat Tail Ammo. This ammo is manufactured using Federal Mil-Spec brass and bullets. This ammo contains a crimped in sealed primer and the case mouth is sealed and has a 55gr. cannelured bullet. It is brass cased, boxer primed, and 100% non-corrosive. It is bulk packed in a 1000rd. case.