CMMG Castle Nut for AR15 Buffer Tube – Receiver Extension Nut, Black (55CA9CB)

• Receiver extension castle nut designed for securing buffer tube assemblies on AR-15 rifles
• Provides secure retention of receiver extension during firearm operation and recoil cycling
• Matte black finish offers corrosion resistance and consistent component appearance
• Compatible with standard AR-15 buffer tube and receiver extension threading
• Used during assembly or maintenance of lower receiver extension systems
• Essential hardware component for proper buffer tube installation and retention

The CMMG Receiver Extension Nut Castle Nut AR-15 Matte Black is a castle nut designed for securing the receiver extension to AR-15 lower receivers. This receiver extension nut threads onto buffer tubes and locks the receiver extension assembly in place. It is designed for compatibility with standard AR-15 buffer tube systems.

The CMMG receiver extension nut fits AR-15 platforms and features a matte black finish. It is categorized as a buffer tube hardware component and installs over the receiver extension threads. The castle nut design allows staking for secure retention during operation. This product is used for assembling or maintaining buffer tube systems for rifle platforms in range use or field setups. In standard configurations, the receiver extension nut secures the buffer tube and end plate to the lower receiver.