So you understand that in addition to needing a new barrel and a bored-out cylinder, you'll need to adjust the space between the rear of the barrel and the cylinder face, and (more often than not) the ratchet must be refitted to the hand and/or the hand replaced, right?
Just checking that you know what you're getting into. This might be relatively straightforward for a lot of gunsmiths, but it takes time to do it right. Time is money, so it's going to be pricey. If it's not pricey, then you have probably found someone who only calls themself a "gunsmith", and really is "someone who thinks they know how to fix guns"