Armaspec Self-Retention Castle Nut 7075-T6 Aluminum FDE AR-15/M4

The Armaspec Self-Retention Castle Nut is a drop-in upgrade for the standard mil-spec castle nut on AR-15 and M4 buffer tubes. It uses patented thread-locking technology that holds the nut in place once torqued to spec - no staking or thread locker required - so the loose castle nut problem common to carbine buffer assemblies is solved without the extra fabrication step.

Machined from premium 7075-T6 aluminum for an excellent strength-to-weight ratio, the nut is finished in a rugged hardcoat anodized Flat Dark Earth coating that resists wear and corrosion through high round counts. It is a direct-fit replacement for mil-spec castle nuts on standard buffer tubes and end plates, making installation a straightforward swap during a build or routine service.

Whether you're assembling a new carbine or chasing down a loose factory nut, the Armaspec Self-Retention Castle Nut delivers a simple, made in the USA solution that stays put shot after shot.