The Mossberg 590 is the heavy-duty sibling of the 500 with a thicker barrel wall, metal trigger guard, and metal safety button rated for prolonged military use. The 20-inch 9-shot configuration holds 8+1 rounds of 2.75-inch shells. Type: Pump Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 9 Year introduced: 1987, USA Weight: 7.25 oz Overall length: 41" Status: Active Military use: Yes Intended use: Tactical, Law Enforcement, Military, Home Defense