Designed to fit your AR-15 pattern rifles chambered in .223 Remington and 5.56x45mm. This drum magazine feeds alternately from the left and right drums with the assistance of two follower belts resulting in a fixed center of gravity while firing. The reinforced feed lips and tension arms are made of solid steel. While a loaded aluminum 30 round magazine weighs about 1.5 lbs the rugged KCI USA drum weighs only 2.2 lbs (1 kg) unloaded and 5 lbs (2.27 kg) loaded. A simple loader is included with each magazine making loading fast and easy. 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.NOT COMPATIBLE WITH SOME AR-15 / M16 / M4 RECEIVERS THAT DO NOT HAVE THE SAME INTERNAL AND EXTERNAL DIMENSION OF A MIL-SPEC LOWER RECEIVER!Specifications Weight: 2.2lbs Compatibility: AR-15 / M16 / M4 Caliber: .223 Remington / 5.56x45mm Capacity: 100 Rounds Body Material: Polymer / Steel Spring Material: Music Wire