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 with 3″ chambers used on Super Magnum and Magnum receivers will handle both 2-3/4″ and 3″ shotshells only. Use only 2-3/4″ shotshells when these barrels are used on non-Magnum receivers. 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.