Fortis Manufacturing, Inc., Castle Nut, Black, Anodized Finish, Mil Spec - CN-Stand - 810103343054
Product Description
Assembling or upgrading an AR-15 receiver extension assembly requires a high-precision castle nut that secures the receiver extension tube firmly against the end plate without stripping threads or adding unnecessary weight. Standard steel castle nuts can be heavy and susceptible to corrosion over time if the phosphate coating wears down during installation. The Fortis Manufacturing Standalone Mil-Spec Castle Nut in Anodized Black (CN-Stand) addresses weight reduction and corrosion resistance by offering a lightweight, aircraft-grade aluminum alternative engineered to exact Mil-Spec thread pitch and outer spanner wrench dimensions.
Precision CNC-machined from 7075-T6 aircraft-grade aluminum, the Fortis CN-Stand castle nut offers exceptional structural integrity while reducing total assembly weight compared to traditional steel components. The precision-cut internal threads ensure smooth, binding-free engagement onto carbine buffer tubes, while the outer notches are shaped to accept standard armorer castle nut wrenches for clean, slip-free torquing.
Finished in a durable, Type III Hardcoat Black Anodize, the Fortis Standalone Castle Nut provides maximum resistance against corrosion, moisture, and chemical cleaning solvents. Engineered for direct fitment across all standard Mil-Spec AR-15 and AR-10/LR-308 receiver extensions, it is the ideal component for custom lightweight builds, bench rest restorations, or lower receiver overhauls.
*Armorer Bench Notes & Real-World Staging Guidance:
Fitment & Platform Compatibility Matrix: Fits standard Mil-Spec and commercial carbine receiver extension tubes (buffer tubes) for AR-15 and AR-10 / LR-308 platforms. Compatible with all standard Mil-Spec AR end plates and QD end plate designs.
Installation & Staking Sequence:
- Safety check the firearm, remove the magazine, lock the action rearward, and physically/visually inspect the chamber to ensure an empty weapon.
- Lightly grease the threads of your receiver extension tube before threading the Fortis castle nut on (smooth edge facing forward, notched side facing rearward).
- Slide your end plate onto the buffer tube and thread the receiver extension into the lower receiver until it depresses the buffer retainer pin.
- Tighten the Fortis castle nut hand-tight against the end plate while ensuring the takedown pin spring and detent remain properly aligned inside the lower receiver.
- Using a torque wrench and standard castle nut armorer wrench, torque the castle nut to 38–42 ft-lbs. Stake the castle nut into the end plate notches using an automatic center punch for duty-grade staging security.
Key Features
- Precision CNC-Machined 7075-T6 Aluminum: Delivers high tensile strength with a fraction of the weight of standard steel castle nuts.
- Mil-Spec Thread & Spanner Geometry: Fits all standard carbine buffer tubes and engages seamlessly with standard armorer wrenches.
- Type III Hardcoat Anodized Black Finish: Guards against surface wear, scratches, moisture, and cleaning chemical corrosion.
- Clean Staking Notch Architecture: Features deep relief notches for positive center-punch staking against end plates.
- Universal AR Platform Fitment: Compatible across standard AR-15, M4, and AR-10 / LR-308 lower receiver extensions.
Product Specifications
- Brand: Fortis Manufacturing, Inc.
- Model: Standalone Castle Nut
- MPN: CN-Stand
- UPC: 810103343054
- Platform Compatibility: AR-15 / AR-10 / LR-308 Receiver Extensions
- Material: 7075-T6 Aircraft-Grade Aluminum
- Finish / Color: Type III Hardcoat Anodized Black
- Weight: 0.2 oz (5.7 g)
