Glock 21 Gen4 MOS full-size .45 ACP with factory optic cut. Brings factory optic mounting to the Gen4 .45 ACP flagship. Type: Pistol Action: Semi-Automatic Caliber: .45 ACP Capacity: 13 Year introduced: 2015, Austria Weight: 26.28 oz Overall length: 7.59" Status: Active Intended use: Competition, Service, Duty