The Colt Rail Gun .45 ACP is a usa-made single-action pistol chambered in .45 ACP, introduced in 2012. Primary use: Carry, Tactical. Type: Pistol Action: Single-Action Caliber: .45 ACP Capacity: 8 Year introduced: 2012, USA Weight: 38 oz Overall length: 8.5" Status: Active Intended use: Carry, Tactical