Those are some great questions. The answers should be obvious but aren't.

If I were to have any gun rechambered I'd reproof the gun. The problem is there is no standard here in the US for doing so, thus most all of this is done on your (our) own. I mean there is no proof on factory rifles in the US so if you say you never buy a gun that wasn't proofed you'd never buy a domestically built gun.

The shotgun action question especially interests me. I say that because I'm currently working on my 5th DR that I've built on a shotgun action. Now I do my own proofing to the point I feel more than comfortable shooting them but I'm not sure I'd want to buy someone else’s conversion (unless you know them and their work). Just because there is no formalized proofing system.

As far as paying the same again it goes back to the work done I suppose. As far as I know none of the larger shops have a formalized "proof" for their guns on rebarrels in bolt guns so why should we expect it in a DR?

As you can see I don't really have answers just giving a few of my thoughts on the topics.

BB