Abstract: A barrel for a muzzle loading firearm. The inner cylindrical surface which defines the bore of the barrel has a main portion which is provided with rifling and a muzzle portion which is integral with the main portion which extends from the main portion to the muzzle opening. The muzzle portion of the inner cylindrical surface has a diameter which is less than the inner diameter of the main portion of the inner cylindrical surface. The barrel of the present invention is made by drilling a cylindrical bore along a longitudinal axis of a solid barrel stock and forming rifling along the inner cylindrical surface which defines the bore with the use of a traditional rifling tool. A counterboring tool is then inserted to the muzzle opening to enlarge the muzzle end of the bore to form the muzzle portion of the inner cylindrical surface.