CMMG's 9 AR Conversion Magazines make it possible to shoot 9mm ammunition from your unmodified AR15 lower receiver when paired with a CMMG 9mm Radial Delayed Blowback (RDB) upper. CMMG's 9 AR Conversion Magazine is a modified PMAG that seats into your AR15 mag-well and holds up to 30 rounds of 9mm ammunition. Its unique design allows it to feed any CMMG 9mm Radial Delayed Blowback (RDB) upper receiver while maintaining last round bolt hold-open functionality. 9A-19 30 Round Capacity Last Round Bolt Hold-Open Magpul PMAG Body, 9ARC Internals Uses Standard Carbine Burffer and Action Spring Weight: 6oz