The Model 597 is easily the most advanced autoloading rimfire rifle ever built, and the most technologically advanced breakthrough in autoloading rimfire rifle technology in 35 years. The difference starts with Remington's proprietary bolt-guidance system, which features a unique set of twin tool-steel guide rails for better stability, feeding reliability and greater out-of-the-box accuracy. The bolt, hammer and sear of the Model 597 all feature an exclusive nickel-Teflon plating for smooth, dependable operation and an ultra-crisp trigger pull. To assure reliable, long-term accuracy, the 597 incorporates a unique positive-locking, permanently rigid barrel attachment clamp. Receivers are grooved for standard rimfire mounts and tapped/drilled for Weaver-style bases. Completing the breakthrough design are an innovative last-shot "hold open" magazine feature and Remington's patented, easy-to-use staggered-stack magazine. The Model 597 AAC-SD features a black synthetic stock and a 16.5" threaded blued barrel with a thread protector. The threaded barrel accepts AAC and other 1/2"-28 threaded flash hiders, muzzle brakes, and suppressors. This rifle has a Weaver-style scope-mounting base, a cross-bolt safety, and a 10-round magazine. Its stock, metal, and bore are all in very good condition.