CMMG MK4 Receiver Extension – Black Steel

The CMMG Receiver Extension MK4 is a buffer tube-style receiver extension intended for AR-15 platforms. It provides the mounting interface for a compatible stock and functions as part of the MK4 receiver extension system. Constructed and finished in steel with black rails, this component matches the form and fit expected for AR-15 extension assemblies.

Key Specifications

• The product type is a Buffer Tube.
• The rails are finished in Black.
• The construction material is Steel.
• The firearm type is listed as Receiver Extension.
• The finish is specified as Steel.
• The listed shipping weight is 0.25.
• The listed weight is 0.25.
• The style is described as Extension.
• The make/model is identified as AR-15.
• The make is recorded as AR-15.

Well-suited for builders and technicians assembling MK4-based AR-15 platforms, this receiver extension offers straightforward compatibility and durable steel construction. It provides a reliable foundation for stock attachment and for completing a functional buffer system during builds or upgrades.