LBE Unlimited ARCNUT Castle Nut 4140 Steel Manganese Phosphate AR-15 Receiver

The LBE Unlimited ARCNUT Castle Nut is crafted from durable 4140 steel finished in manganese phosphate, delivering reliable hardness and corrosion resistance for AR-15 builds where dependable a locking mechanism is essential. This castle nut combines a robust design with precise tolerances to ensure secure installation on your rifle, maintaining proper staking and spring tension for consistent performance under demanding conditions. Ideal for builders and upgrades, its manganese phosphate finish provides low glare, subtle wear resistance, and a professional, aircraft-grade appearance that complements a wide range of rail systems and upper receivers. The ARCNUT's construction and finish are suited for long gun applications where durability and repeatable torque are important, helping you maintain a solid muzzle-end lock even after repeated field use. Whether you're completing a new build or upgrading worn components, this castle nut from LBE Unlimited offers a reliable interface for your receiver extension, contributing to smooth operation, straightforward maintenance, and long-term peace of mind in the field or at the range.