Whether you’re enjoying a day at the range, confronting an adversary on the battlefield, or defending your home, maximize your stopping power with the CMMG® 5.7x28mm AR-15 10-Round Conversion Magazine (3 Pack). Compatible with any standard AR-15 lower receiver (not included), these 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.