Use of lathe is best
Hand powered barrel crowning tools are nice to use and have but
For one barrel not worth it.
You can cut/crown a barrel with a hacksaw and square the end with a file and lap the crown with a brass screw.
It does not matter the method as long as the crown is ninety degrees and concerntric to the bore.
CW Shooters Supply Inc
Machine Shop and Finishing Services to the trade and public