The Forward Controls Design Castle Nut (FCD part no. CNF (CASTLE NUT) ODG) is machined from billet stock rather than cast, finished in a Burnt OD Green color, and built to clamp an AR-15 receiver extension to the lower receiver. Billet construction gives the nut cleanly cut, uniform threads and flats compared with a cast factory nut, and the Burnt OD Green finish lets it double as an accent color on a build.

Key Specifications

• machined from billet stock giving cleanly cut, uniform threads compared with a cast factory nut.
• Burnt OD Green finish an accent color option for a build’s furniture.
• secures the receiver extension clamping it to the lower receiver to eliminate stock play.

Frequently Asked Questions

What does a castle nut do? It clamps the receiver extension (buffer tube) to the lower receiver, eliminating stock play.

Why billet instead of cast? Billet machining gives cleanly cut, uniform threads and flats compared with a cast nut.

Buy the FCD Billet Castle Nut

Add a color-matched billet castle nut to an AR-15 build. Browse more of our rifle parts selection and order from our Lubbock, Texas gun shop for fast shipping.