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