CMMG 4.6x30mm AR-15 40-Round Conversion Magazine

Constructed of an impact-resistant polymer and compatible with any standard AR-15 lower receiver, the CMMG® FourSix™ 4.6x30mm AR-15 40-Round Conversion Magazine safely feeds 4.6x30mm ammunition for reliable operation with your CMMG FourSix complete upper receiver (not included). Better yet, this magazine features a last-round bolt hold-open functionality for a clear indication of an empty magazine and faster reloads.