The Primary Weapons Systems 4G2BTPB-1F Castle Nut, finished in durable Black Anodized on 7075 T-6 Aluminum, delivers a purpose-built upgrade for sleek, reliable AR platform performance with a weight of 4.3 oz. Its Mil-Spec tube diameter and impact-extruded construction provide a robust foundation, while the extended carrier support lip enhances smoother cycling under demanding conditions. The design features lightening cuts that shave approximately 1 oz from traditional profiles, contributing to a lighter overall balance without sacrificing strength. A distinctive fluted tube design aids debris clearing, helping maintain consistent operation in challenging environments, and the MIL-A-8625 Type III, Class 2 anodized finish adds long-lasting corrosion resistance. Meticulously engineered to integrate with standard components, this castle nut set includes a PWS ratchet lock castle nut and end plate, ensuring secure, repeatable torque and reliable locking engagement. Ideal for builders seeking enhanced reliability, smoother cycling, and weight-conscious performance, the 4G2BTPB-1F combines proven PWS engineering with a refined aesthetic to support precise, confident field use and maintenance-friendly upgrades.