Manufactured by CNC Warrior and precision-machined from aircraft-grade aluminum. This hinge is designed to lock up solid, even tighter as wear ensues, and provide years of trouble-free use while maintaining its light weight. Includes a hardened steel bushing around the hinge pin to prevent wear, and chrome plated stainless steel spring with ground ends. Contoured to match your rear trunnion, this stock provides a nice factory look and installs without the use of any adapters and without requiring modifications to your rifle firearm. All models have an extra deep QD sling swivel pocket and finished in Class III black hard coat. All parts and material are MADE IN USA, right down to the spring, pin, and e-clip. SAM7k (original w/ rear sling swivel) - This hinge mounts to the original SAM7k after removing the sling swivel on the rear of the receiver and is 8"