Looking for something else, I came across this listing:

http://www.gunsinternational.com:80/Winchester-model-70-pre-64-416-Rigby.cfm?gun_id=100118176

I was taken aback, because I had never seen or heard of a .416 Rigby on a Model 70 action. I wonder if anyone else has heard of such a thing or has had experience with one. I have a pre-64 Model 70 in caliber .375 H&H which has had the barrel cut back to 22" and would be a likely candidate for this conversion, if it is a practical one.

One of my concerns is that the .375 H&H cartridge is .120" shorter than the .416 Rigby, and the Model 70 magazine box is already stretched to accomodate the .375. Another is that the Model 70 bolt face might not be large enough in diameter to safely accomodate the Rigby case head.

Still, it seems unlikely that Griffin and Howe would undertake such a project if they didn't think it would work flawlessly.

Comments, anyone?