The Smith & Wesson Model 640 was introduced in 1990 and has been modified several times over years. Model 640 is also built on Smith & Wesson J-Frame, a frame that is generally intended for small, compact, and concealable revolvers. Even though the gun is quite small, it is chambered in .357 Magnum, and can also fire shorter .38 Special ammunition. It is double-action-only, with a capacity of 5 rounds. The barrel is only two inches long. This model is an all-steel gun which means most of its parts are made of stainless steel. The synthetic finger-grooved grips allow a firm and tight squeeze. The gun also has a small internal hammer that helps with concealment and prevents the revolver from snagging on clothes. Overall, this is a small-size, concealed carry revolver but also very powerful, recommended for beginners with .38 Special rather than with .357 Magnum, considering the fact that magnum bullets give more recoil and are more difficult to handle.