CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine. These Gen II 9mm magazines work in Mk4/AR15 lower receivers with a CMMG 9mm Radial Delayed Blowback upper and feature the iconic CMMG styling with MORE capacity than the Gen 1 magazines 33rd vs 30rds. Exterior dimensions closely match those of common 5.56 AR15 magazines for cross-compatibility with existing mag pouches and carriers. Specifications for CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine: Manufacturer: CMMG Magazine Capacity: 33 Round Caliber: 9mm Luger Gun Make: CMMG AR Platform Gun Model: CMMG Mk4 AR-15 Gun Type: Rifle Condition: New Features of CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine Lifetime Quality Guarantee Package Contents: CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine What firearm models does the manufacturer say CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine is compatible with? The manufacturer suggests that CMMG Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine is compatible with AR-15 CMMG Mk4CMMG 94AFC9F: Mk4/Ar15 Gen 2 9mm 33 Round Pistol Magazine