Mossberg 590A1 military-spec pump with 20-inch barrel, heavy-walled barrel, and parkerized finish. Type: Shotgun Action: Pump Caliber: 12 GA Capacity: 9 Year introduced: 1987, USA Weight: 7.5 oz Overall length: 41" Status: Active Military use: Yes Intended use: Military, Law Enforcement, Defense, Military/Tactical