I would just buy the new barrel. that way if you wanted to use your gun for hunting you can just switch barrels.
Chokes. do not use wit slugs the can tear up your barrels and possible you in the process.
if you wanting a tighter pattern. Use Federal tactical buckshot. we use that in law eforcement and holds a tight pattern. I have shot it out of 14 inch barrel at 25 yards and all pellets were on target. most other buckshot rounds do not hold that tight.
Chokes. do not use wit slugs the can tear up your barrels and possible you in the process.
if you wanting a tighter pattern. Use Federal tactical buckshot. we use that in law eforcement and holds a tight pattern. I have shot it out of 14 inch barrel at 25 yards and all pellets were on target. most other buckshot rounds do not hold that tight.