Well, I have participated in crowning of a lot of barrels many way. First is the old standby : the lathe. results as usual very good .
Next I seen a re-crown job done by the same gunsmith, with a hacksaw, file, and a ball-bearing. The end of the barrel was cut with a sharp hacksaw. Then the surface was trued and smoothed with a good mill file. Then the finishing of the crown was done with a ball-bearing and lapping compound. The results was just as good as the crown done on a lathe. But a lot more time and attention to detail is required! The barrel was a couple of heavy varmint barrels. This was to show me it could be done, and also some benchrester actually use this method to " clean up" their crowns!!
Finally the last crowning method is done by a specialize "crown cutter" this was done on some service revolvers. When done correctly this had respectable results also So depending on what resources you have available to you or how much you are willing to invest. There are options you can choose from