Re: Sever throat erosion can bbl be saved
First, it needs to be bore scoped to see entire condition. My BR gunsmith says: If the bore is not firecracked, a re-chambering will restore some accuracy for a limited number of rounds. In the 6PPC, he recommends rechambering only if it does not have more than 1,800 rounds thru it.
Before you re-chamber to a new caliber, what is current bolt face opening; and what twist is it now? In the new chamber, what bullet will you use and will it be stabilized by that weight? These answers may suggest the proper caliber.