If you want a big game calibre on a standard mauser action with factory fodder available it's hard to beat the 458 Win - very boring choice.

I have two magnum mausers that will be built to 416 Rigby and 375 Blaser.

Early ZG-47s are very nice and well made. ZG-47 action can easily modified to take 404 Jeffery but ejectionport must also be opened.