Re: Mauser 98 375 H&H questions
Technically, the proper length of a 375 H&H cartridge is 3.6, 30-06 goes 3.34, and 8x57, intended for most German made Mausers, is 3.228. You could probably stuff a 375 into a 30-06 action by taking another 10 thou off the case and using short bullets, but that is not really a 375 H&H anymore, and the case does not have a very long neck to begin with, so it might not grip the bullet right. In my experience, 30-06 length Interarms actions have a pretty generous mag box, but all Interarms are not the same. What you really want to avoid is an action that has had metal removed from the feed ramp area to accommodate a longer cartridge, since the action is now weakened and not safe.
Jerry Kuhnhausen's book "The Mauser Bolt Actions, a shop manual", is absolutely essential for anyone fiddling around with Mausers. He cover all this and a lot more. I am NOT quoting him on whittling down the 375 to make it work - his advise is get a magnum action. Of course, boys will be boys, and sometimes you just gotta try something. I went through all this setting up a 30-06 length Interarms for 404 Jeffery, a cartridge that falls between standard and magnum length. Be aware that the Interarms action is a super-hard alloy that is very frustrating for someone with a hand file or rotary tool, not at all like the gun steel of the early or mid 20th Century, so you should find a 7 Mag, 300 Mag or anything else that already feeds the belted case.