There is a Youtube series called C&Rsenal that occasionally has a gunsmithing video showing what their gunsmith calls home project smithing. I remember one two part series on restoring antique military rifles without altering them and ruining their historical value. At the end of one process, restoring the original finish, he made the statement that most gunsmiths would not want to do the work. They would have to charge a whole lot more than the rifle is worth, for the time they were spending on the firearm. I think this is probably the reason you won't be able to find a gunsmith to do the work for you. It's more profitable to just change a part than to troubleshoot and possibly have to fabricate a replacement part. If a gunsmith did take in an older rifle and had to spend a lot of time on it, the owner might retch at the price to fix it, and to be sure, there is no way to know how much time you're going to have to spend on it. Pawpa's heirloom Winchester might have a lot of sentimental value until you realize you can get two for what you're going to have to pay to fix it.