The Remington 870 Marine Magnum is fully nickel-plated inside and out for maximum corrosion resistance. 18-inch cylinder-bore barrel with a 7-shot extended magazine. Synthetic stock. The benchmark for stainless/nickel-finish defensive shotguns. Type: Pump Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 7 Year introduced: 1986, USA Weight: 7.5 oz Overall length: 38.5" Status: Active Intended use: Home Defense, Marine, Tactical