New thompson center 56 cal hexagon smooth bore 27" rifle / shotgun barrel 1 inch between flats.  Fits Thompson sidelock renegade/ new englander and hawkins rifles. This is a (new) old enventory item that appears to be unfired.  This was a special order item from Thompson center. The advantage with a smooth bore rifle barrel is accuracy, extra knock down power and the option of using it as a 28 gauge shotgun or 56 cal rifle.  This means you can switch to a shotgun or back to a rifle without carrying two guns.  Also makes a good slugster.  This barrel shoots a massive 56 cal ball that doses maximum damage allowing the user the capabilite of harvesting larger animals like elek, bear, and mule deer with only on"e well placed shot.  If your a one Thompson muzzleloader rifle owner, the shotgun option is like getting two guns in one.  And if you have never owned a muzzleloader shotgun your in for a pleasant experience.