Done what Aalf n Mule Deer has done, worked great, later had a smith clean up for cosmetic reasons. When you cannot be happy with a barrel that is too long for your purpose, you will wonder what took you so long to shorten it.
Likewise, if you suspect or KNOW your crown is bad, cleaning up with a chamfer tool and/or the brass screw method can do alot of good.
What Yukoner said, is what I did, plug the bore near muzzle end to keep debris out the bore. Cleaning patch can work, push thru when done, and a few more from chamber end only.