This is Winchester 5.56 Q3131A1 55gr. M-193 FMJ ammo. This ammo is manufactured by PMC for Winchester to M-193 U.S Military Spec's and is headstamped WCC. It is brass cased, boxer primed, non-corrosive and 100% new factory ammo. This is some great ammo to blast with. It is clean and reliable. This ammo is packed in 20rd. boxes, 1000rds. per case.