The Mossberg 590A1 Special Purpose is a factory-configured tactical variant with an M-LOK forend, ghost-ring rear and XS front sight, and a heavy parkerized barrel meeting all military specifications. Type: Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 8 Year introduced: 1987, USA Weight: 8 oz Overall length: 39.5" Status: Active Military use: Yes Intended use: Military/Tactical