The GP100 is Ruger's workhorse mid-frame double-action revolver, built on a triple-locking cylinder and full-length frame lug. The triple-locking cylinder locks at the rear, front, and crane — making it one of the strongest .357 Magnum platforms ever produced. The 4.2-inch barrel is the most popular configuration. Standard across LE agencies that carried DA revolvers in the 1980s and 1990s. Type: Revolver Action: Double-Action / Single-Action Caliber: .357 Mag Capacity: 6 Year introduced: 1985, USA Weight: 36 oz Overall length: 9.5" Status: Active Intended use: Duty, Self-Defense, Hunting, Range