Upper Receiver Assembly, Mk4/AR15

Expertly crafted from aircraft grade aluminum, CMMGMk4/AR15 upper receiver assemblies come with our ZEROEDPolymer 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 CompatibilityFeaturing 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.Lifetime Quality GuaranteeWe aim to please, that's why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.