The Mossberg 500 Pistol-Grip Shotgun is a pump-action shotgun from Mossberg . Specifications vary depending on the gauge, barrel length, and exact model configuration. Gauge: Commonly 12 gauge Action: Pump action Barrel length: Commonly 18.5 inches Capacity: Commonly 5+1 rounds Chamber: 3 inches Overall length: Approximately 28.75 inches Stock/grip: Pistol grip only Finish: Typically black matte Sights: Bead sight