| Platform | Mk4 |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Finish | Cerakote Standard |
Expected to ship within 15-30 business days. AR Parts Notice - State/local restrictions may apply in CT, DC, IL, MA, NJ, NY, or WA. Customers must review our Shipping Policy prior to ordering.
Upper Receiver Assembly, Mk4/AR15
Expertly crafted from aircraft grade aluminum, CMMG® Mk4/AR15 upper receiver assemblies come with our 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.
Lifetime Quality Guarantee
We aim to please, that’s why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.