The Mossberg 590 is the civilian and law enforcement variant of the military 590A1, sharing the same long magazine tube and 20-inch barrel but with a standard aluminum trigger guard rather than the mil-spec steel version. Type: Pump-Action Shotgun Action: Pump-Action Caliber: 12 GA Capacity: 9 Year introduced: 1987, USA Weight: 7.5 oz Overall length: 40.5" Status: Active Intended use: Tactical, Law Enforcement, Home Defense