The round-butt 4-inch Model 66 combined the standard duty barrel length with the rounded grip frame for officers who preferred that grip geometry. It was produced in quantity for departments and agencies with specific round-butt holster requirements. Type: Revolver Action: Double-Action Caliber: .357 Magnum Capacity: 6 Year introduced: 1975, USA Weight: 36 oz Overall length: 9.5" Status: Discontinued Intended use: Duty, Service