The .45 Colt/.45 ACP Convertible Blackhawk ships with two cylinders, one for .45 Colt and one for .45 ACP with moon clips. The .45 ACP cylinder allows the shooter to run inexpensive .45 ACP pistol ammunition in a single-action revolver, while the .45 Colt cylinder enables the full classic cartridge experience. The 5.5-inch barrel is standard for this variant. Type: Revolver Action: Single-Action Caliber: .45 Colt / .45 ACP Capacity: 6 Year introduced: 1971, USA Weight: 42 oz Overall length: 11.2" Status: Active Intended use: Recreational, Cowboy Action Shooting, Hunting