Rifled barrel having a rifled and non-rifled portion

1. A rifled barrel, comprising:

a cylindrical channel longitudinally extending within the rifled barrel between an oppositely oriented muzzle opening and a breach opening, the cylindrical channel having a rifled portion and a non-rifled portion,

the rifled portion having a land and a groove helically extending along a surface of the cylindrical channel from the muzzle opening toward the breach opening,

the non-rifled portion being smooth and having a consistent diameter along an entire length of the non-rifled portion,

wherein the diameter of the non-rifled portion of the cylindrical channel is equal to a diameter of the rifled portion measured between oppositely oriented sections of the groove along an entire length of the rifled portion, and

wherein a diameter measured between oppositely oriented land sections of the rifled portion along a partial length of the rifled portion adjacent to the non-rifled portion gradually increases until equaling the diameter of the non-rifled portion.

2. The rifled barrel of claim 1 , wherein the length of the non-rifled portion is configured to accommodate a cylindrical body of a projectile.

3. The rifled barrel of claim 1 , wherein the non-rifled portion of the cylindrical channel is insertably removable from the barrel through the breach opening.

4. A muzzleloader firearm comprising at least the rifled barrel according to claim 1 .

5. A breechloader firearm comprising at least the rifled barrel according to claim 1 .

6. A method of converting a fully rifled barrel to a partially rifled barrel, comprising:

reducing lands located along an inner surface of the rifled barrel along a partial length of the barrel such that the lands are fully removed along the partial length to form a non-rifled portion,

partially reducing lands along the inner surface of the rifled barrel along a partial length of barrel adjacent to the non-rifled portion such that a diameter between oppositely oriented lands gradually decreases along the partial length toward a muzzle end of the partially rifled barrel,

and maintaining a consistent diameter throughout the length of the partially rifled barrel measured between oppositely oriented sides of the non-rifled portion and between oppositely oriented grooves of a rifled section of the partially rifled barrel.

7. A rifled barrel, comprising:

a rifled portion extending longitudinally along the rifled barrel, and having helical lands and helical grooves extending longitudinally along a cylindrical surface of the rifled portion,

a non-rifled portion extending longitudinally along the rifled barrel, and having a smooth cylindrical surface, the smooth cylindrical surface having a consistent diameter along an entire length of the non-rifled portion, and

a transitional portion of the rifled portion extending longitudinally along the rifled barrel adjacent to the non-rifled portion and having sloped helical lands and transitional helical grooves,

wherein the consistent diameter along the entire length of the non-rifled portion is equal to a diameter of the rifled portion measured between oppositely oriented helical grooves, and the diameter of the rifled portion measured between the oppositely oriented helical grooves is consistent along an entire length of the rifled portion.

8. The rifled barrel of claim 7 , wherein a diameter of the transitional portion measured between oppositely oriented sloped helical lands increases along a length of the transitional portion toward the non-rifled portion.

9. The rifled barrel of claim 7 , wherein the entire length of the non-rifled portion is configured to accommodate a body of a projectile.

10. The rifled barrel of claim 7 , wherein the non-rifled portion is insertably removable from the rifled barrel.