The Mossberg 590A1 with a 20-inch barrel offers one additional round of capacity over the 18.5-inch variant while retaining all heavy-duty military-specification features including a parkerized finish and metal trigger group. Type: Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 9 Year introduced: 1987, USA Weight: 8.25 oz Overall length: 41" Status: Active Military use: Yes Intended use: Military/Tactical