If you want to do it yourself, the Manson crowning tool is a REALLY nice piece of gear.
You could always sell it somewheredown the line.
I chucked it up in a good cordless drill, used lots of cutting oil, and frequently blew the chips away with compressed air.
Face back the crown with the 0-degree facing tool enough until you see sharply defined lands with a magnifying glass.
Barrel steel is pretty soft, but sometimes it takes awhile. Just be patient, use, a steady hand, even pressure, and enjoy the work.
It's a fine feeling, cutting a new crown and seeing accuracy restored.
http://www.brownells.com/gunsmith-t...amers-muzzle-crown-refacing-kit-prod7718.aspx