This Upper Receiver Assembly from CMMG (CMMG part no. 55BA290MB) is compatible with CMMG’s MK4 platform and standard AR-15 lower receivers, finished in Midnight Bronze as one of CMMG’s color-matched upper options.

Key Specifications

• Compatible with CMMG’s MK4 platform and standard AR-15 lower receivers.
• Finished in Midnight Bronze.
• Sold as an upper receiver assembly.
• Part of CMMG’s line of color-finished AR-15 upper options (tan, bronze, and tungsten variants).

Frequently Asked Questions

Does this include a bolt carrier group or barrel? Check the specific listing details for included components; confirm with us before ordering if you need a fully barreled, complete upper rather than the receiver assembly alone.

Is this compatible with a standard mil-spec AR-15 lower? Yes, it’s built to mate with standard AR-15-pattern lower receivers as part of CMMG’s MK4 platform.

Buy the CMMG MK4/AR15 Upper Receiver Assembly, Midnight Bronze

Match your build’s finish with this Midnight Bronze CMMG MK4/AR15 upper receiver assembly. It ships fast from our Lubbock, Texas gun shop, and our AR-15 uppers selection has more AR-15 upper receivers.