CMMG 5.7x28mm AR-15 40-Round Conversion Magazine (3 Pack)

Convert any Mil-Spec AR-15 lower receiver to safely fire popular 5.7x28mm cartridge with the CMMG® 5.7x28mm AR-15 40-Round Conversion Magazine (3 Pack). These double-stack CMMG conversion magazines safely feed 5.7x28mm ammunition for reliable operation with your CMMG 5.7x28mm Radial Delayed Blowback complete upper receiver (not included). Constructed of durable, high-impact polymer, these magazines feature a last round bolt hold-open functionality for clear indication of an empty magazine and faster reloads.