arweightfourfourtytwo, I realize many people don't have the knowledge, skills, or self confidence to work on their own guns but crowning a muzzle is about as simple as you can get. Anyone with the mechanical aptitude of a carrot can do it.
1. Buy a 45 deg cutter with brass pilot. Part number 080-948-380WB, $101 at Brownell's. See: BROWNELLS 45° MUZZLE/CYLINDER CHAMFERING CUTTER & BRASS PILOT | Brownells
2. Buy a 45 deg brass muzzle lap. Part number 080-624-045WB, $15 at Brownell's. See: BROWNELLS 45° BRASS MUZZLE LAP | Brownells
3. Hand ream the crown using cutting oil. The pilot will keep the cutter centered in the bore. When you see a fresh cut all the way to the lands, stop.
4. Use the 45 deg brass lap in an electric drill to finish the job. Once the fresh cut is polished, stop.
For the price of the tools, a gunsmith can do several guns so it's not the difficulty level, it's more about the cost. If you want to recrown several guns, it will be more cost effective to own the tools. Before you even think about ordering the tools, take blackvoid's advise and look at the referenced thread.