Smith & Wesson Model 640

The Smith & Wesson Model 640 revolver is a 5-shot snubnosed revolver that is chambered in either .38 Special or .357 Magnum calibers. Like nearly all other "J-frame" Smith & Wesson revolvers, it has a swing-out cylinder, but this model features a concealed hammer. It has been in production since 1990 and is part of the Centennial line.

The first model was chambered in .38 Special and fitted with a standard barrel of 1-7/8 inch length. The second model had a slightly heavier and longer barrel of 2-1/8 inch length. The gun was constructed entirely of stainless steel until 1995, when models were made in aluminium and designated "airweight".

A 3" barreled version was offered until 1993, when it was dropped from production. That same year S&W introduced the Model 940, similar in appearance, but chambered in 9mm Luger.  In 1996 the 940 was dropped and S&W began chambering the 640 in .357 Magnum.  Because of the power of the .357 magnum cartridge, the frame is strengthened just in front of the cylinder release on those models.

In 2001 a Scandium framed version was introduced in .357 Magnum designated as the Model 340. This revolver weighed 10.9 ounces.

In spite of its small frame and short barrel the gun is durable and fairly accurate. Firearms writer, Joe Gorman, fired 500 full power rounds through the revolver and it survived still tight and still in time.