If you are going to let a gunsmith thread it........ Don't leave it with one who can't give you a completion date. I have had a barrel at 2 different smiths for 12 months (6 months each) and never got it threaded. If one will put you on his waiting list and allow you to bring it in the day he will thread it, that would be acceptable.
I know, I know there are 100's of guys who have a smith who will thread it in a few days... Save those replies, I've heard all of them.