The Smith & Wesson Model 640 Centennial is an all-stainless J-Frame with fully concealed hammer and .357 Magnum rating. Its double-action-only operation and snag-free profile make it a favored deep concealment option. Type: Revolver Action: Double-Action Caliber: .357 Mag Capacity: 5 Year introduced: 1991, USA Weight: 23 oz Overall length: 6.625" Status: Active Intended use: Concealed Carry