The Model 597 with scope starts with the 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. Of course, Remington didn't stop there, 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, Remington also incorporated 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 the patented, easy-to-use staggered-stack magazine.These guns have 5R rifling.