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 our 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. he sear of the Model 597? features an exclusive nickel-Teflon® plating for smooth, dependable operation and an ultra-crisp trigger pull. 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 our patented, easy-to-use staggered-stack magazine.