The Smith & Wesson Model 500 is a five-shot, double/single action large-caliber revolver produced by Smith & Wesson, firing the .500 S&W Magnum cartridge. The Model 500 was built on the entirely new X-Frame, [2] which was developed exclusively to handle the immense muzzle velocity and pressures generated by firing of the .500 Magnum cartridge. [3]