CMMG Mk4/AR15 Armor Black Upper Receiver Assembly (55BA290-AB)

Expertly crafted from aircraft grade aluminum, the CMMG Mk4/AR15 Upper Receiver Assembly comes with their ZEROED Polymer Dust Cover pre-installed. Available in seven different Cerakote finishes, this upper receiver omits the forward assist for those looking for a sleek and stylish base to start a new AR15 build.

PCC Compatibility
Featuring an enlarged ejection port, the CMMG Mk4 upper receiver can accomodate a variety of pistol calibers like 9mm, 10mm, .40 S&W, and .45 ACP and is compatible with CMMG MkG, MkGs, Mk10, Mk9, and Mk17 lower receivers. NOTE: This upper is not compatible with CMMG fixed ejector Radial Delayed Blowback BCGs.