Smith & Wesson "N" to the largest .44 Magnum type frame. In 2003, the even larger "X" frame was introduced for the .500 S&W Magnum. Most Smith & Wesson revolvers have been equipped with an internal locking mechanism since the acquisition by Saf-T-Hammer. The mechanism is relatively unobtrusive, is activated with a special key, and renders the firearm inoperable. While the lock can simply be left disengaged, most gun enthusiasts prefer "pre-lock" guns. In 1953 the U.S. Army was looking for a pistol to replace the Colt 1911A1. To obtain a bid from the U.S. Government, Smith & Wesson began working on a
Smith & Wesson Model 10 models did use a checkered grip, most notably the pre-1942 manufacture. After World War II, Smith & Wesson returned to manufacturing the M&P series. Along with cosmetic changes and replacement of the frame fitting grip with the Magna stocks, the spring-loaded hammer block safety gave way to a cam-actuated hammer block that rode in a channel in the side plate (Smith 1968). In 1957, Smith & Wesson adopted the convention of using numeric designations to distinguish their various models of handguns, and the M&P was renamed the Model 10. The M&P/Model 10 has been available in both blued steel finish