CMMG Mk4/AR15 Upper Receiver Assembly — Armor Black

The CMMG Mk4/AR15 upper receiver assembly provides a factory-configured platform for AR-15 builds. The receiver is crafted from aircraft grade aluminum and ships with a ZEROED Polymer Dust Cover pre-installed. This assembly omits the forward assist to present a streamlined profile for custom builds.

Key Specifications

• The receiver is made from aircraft grade aluminum.
• Chambering is 223 Rem/5.56 NATO.
• The barrel measures 14.5 inches.
• The barrel material is steel.
• The barrel finish is matte black.
• The rifling twist rate is 1:7".
• Includes a pre-installed ZEROED Polymer Dust Cover.
• The design omits the forward assist for a streamlined profile.
• The exterior finish is specified as Armor Black.
• Shipping restriction: no direct ship to California.

This upper receiver assembly is a practical, no-nonsense choice for builders who want a durable, factory-configured foundation for an AR-15 platform. Its combination of aircraft-grade receiver construction, verified chambering, and integrated dust cover makes it a straightforward option for precision builds and platform customization.