Remington Tac-14 pump 12 gauge accepts 3” rounds, holds 5 in the magazine and one in the chamber.  This has a 14 inch barrel However th BATF does not require special paperwork or tax stamp, they have classified this a a firearm with no restrictions.  However please be aware that any state may have their own restriction regard this “firearm”.  Check with local state authorities and licensed dealers as to laws in your area.