I think this has been done, but I cannot remember the name that it was given. I think the eaisest thing to do will be to have the die made and just use .375 Win brass to form it. We use the .375 brass to make 7-30 Waters rather than fireforming the .30-30. IT takes less time, less cost and you en up with thicker necks that don't crush in loading. Dependin on what you want to do with it, I think you could fully blow out the body, run the shoulder at about 35deg, and shorten up the neck. It would certainly be a good project. I'll dig through my stuff and see if I cannot find the name.