This replacement part is a factory original from Remington. Factory replacement parts are manufactured to the exact same specifications and tolerances and use the same manufacturing materials as the original parts which guarantees excellent fit and reliable operation. Notes: Model 870 extra barrels are chambered for up to 3 1/2" shells. DO NOT use 3/12" shells unless the barrel is mounted to a Remington 870 Super Mag Receiver. Use only the length of shells that are compatible with your receiver make.20 gauge 870 Lightweight barrels will not fit 20 gauge standard 870 shotguns with serial numbers ending in a "X" or "N"Cantilever Rem Choke deer barrels are supplied with improved cylinder and extended rifled choke tubes.Rifle-sighted Rem Choke deer barrels are supplied with rifled and improved cylinder choke tubes.Express 20 gauge fully rifled deer barrel has a 2-3/4" chamber. Model 870 extra barrels with 2 3/4" chambers will fit both Magnum and 2...