Re: Remington 700 in 7.62x54R?
I kind of wanted to do this myself, since I had a magnum bolt but don't really like magnum cartridges. It would be fairly expensive to do, even if you were only planning on a single shot.
You won't be able to use the standard extractor, since the front part of the bolt will need to be cut back almost to the face to allow for proper headspacing. This means you will have to use a claw style extractor such as the Badger or Sako. Another problem you'll encounter is that since the 700's extractor rotates with the bolt, you'll need a radial extractor cut like you'd find on a 91/30.
There are, of course, more little details that would need to be addressed, but the crux of the matter is that it wouldn't be as simple as opening up the bolt, setting the barrel back, and rechambering. If you wanted to put the money into it though, it would certainly be possible to do.