The Armaspec Self-Retention Castle Nut AR-15 FDE is engineered to simplify buffer tube installation while delivering a secure, repeatable lockup on your AR-15 or M4 platform. Machined from lightweight aluminum and finished in a flat dark earth anodized coating, this castle nut uses a unique thread geometry that locks firmly against the end plate, removing the need for staking or thread locker during assembly.

This model is ideal for builders and enthusiasts who frequently change stocks or receiver extensions and want a clean, damage-free installation. Its standard AR-15 receiver extension threads make it a natural fit for mil-spec tubes and common end plates, while the reduced weight helps balance the rifle at the shoulder. Whether you are setting up a dedicated range rifle, a training carbine, or refreshing an existing build, this castle nut reflects Armaspec’s focus on thoughtful design and dependable performance.

Key Features:

• Manufacturer: Armaspec
• Model: Self-Retention Castle Nut AR-15 FDE
• Compatible With: AR-15/M4
• Color: Flat Dark Earth
• Material: Aluminum
• Finish: Anodized