Smith & Wesson Model 640

The Smith & Wesson Model 640 is a five-shot snub-nosed revolver made by Smith & Wesson in the United States and introduced in 1989. It was first chambered in .38 Special, and from 1996 the company also offered it in .357 Magnum, which led to a strengthened frame just forward of the cylinder release on those versions. The gun is built entirely of stainless steel and is a J-frame revolver with a swing-out cylinder, but it has a concealed hammer and belongs to the Centennial line, so it is fired double-action only. The first version carried a barrel of about 1-7/8 inches, a second version had a slightly longer barrel of 2-1/8 inches, and a three-inch variant was offered only until 1993. A lighter aluminium-framed sibling, the Model 642, followed in 1995. The page describes the Model 640 as a service revolver; it names no armed force that adopted it.