This is a factory replacement/extra barrel for the Mossberg 500 or Maverick 88 12 gauge shotguns. It's a rifled bore barrel with a adjustable rifle sights or fantastic accuracy. It must be used with models that have a 6 shot mag tube and it is not compatible with extended magazine tubes. Get into the field and hunting with a Mossberg Shotgun Slug Barrel! - Mossberg 500 Shotgun Slug Barrel 90121 - 12 Gauge - 3 Chamber - 24 Length - Rifled Bore - Adjustable Rifle Sight - Matte Blued - Weight 2 Pounds 8 Ounces - Fits: Mossberg 500 and Maverick 88 12 Gauge with 6 Shot Magazine Tube