CMMG 5.7x28mm AR-15 40-Round Conversion Magazine

Designed for superior performance with any standard AR-15 lower receiver (not included), the CMMG® 5.7x28mm AR-15 40-Round Conversion Magazine delivers reliable firepower and smooth operation with CMMG 5.7x28mm Radial Delayed Blowback complete upper receivers (not included). Constructed of durable, high-impact polymer, this magazine features a last round bolt hold-open functionality for clear indication of an empty magazine and faster reloads. Better yet, the CMMG conversion kit is a drop-in part, allowing for quick and easy installation.