I believe you can get them from a custom makers in most modern chamberings, but they run about $6000. That price shows how well the originals were made and why they are and will be so valuable.
I have one in 300, from the early 40's I think. I love to find one that was rechambered in 270 savage (wildcat), a very intriguing round IMO. It isn't very practical but would be cool to own.