The Model 640 Pro Series is a factory Performance Center upgrade featuring a ported barrel, tuned action, and Hi-Viz front sight. It delivers faster follow-up shots with .357 Magnum by managing muzzle rise. Type: Revolver Action: DAO Caliber: .357 Mag Capacity: 5 Year introduced: 2005, USA Weight: 23 oz Overall length: 6.6" Status: Active Intended use: Carry, Competition