KCI USA Drum Magazine, 223 Remington/556NATO, 50 Rounds, Fits AR-15, Black KCI-MZ036 For AR-15 pattern firearms chambered in 5.56x45mm or 223 Remington. The drum feeds alternately from the left and right sides using two independent follower belts to maintain a balanced center of gravity while firing. Features steel reinforced feed lips for added durability and reliable feeding. This package includes the KCI USA 100 Round Drum" Operator's Manual" Carrying Pouch" Graphite Lubricant" and Loader. Disclaimer: Lifetime Warranty VOIDED if customer disassembles magazine! This magazine is not designed to be used with hollow point ammo.