bronko22000 knows who the person is. I believe it to be Bob Hoyt. Phone number 717-642-6696.
But I think I would decide what size bore I wanted and get a new IBS (Interchangeable Barrel System) barrel from Green Mountain. That's what I did.
http://www.gmriflebarrel.com/search....arrel%20systym But I still have to fiure out what to do with my rusty old .54 cal. barrel. Have you gotten all the rust out? Check out this post. 54 Cal. Evapo Rust Treated Renegade barrel targets. If you go down to about the forth reply it is made by bronko and you will see the info on the person who rebores barrels.
http://www.huntingnet.com/forum/subs...er=desc&page=2
If you have not taken care of all of the rust I have plenty of experience with that and can give you some very good advice.