Gordon
Member
Some talk about .400 whelen type .30-06 Cartridges. Well you really need a shoulder on a rimless bottle neck cartridge unless you machine a stop in chamber to limit brass length , like a .45acp has. The .400 whelan ish types were proven a very long time ago to be troublesome and so were the efforts trying to get it to work . You shoupt consider stopping at the good 9.3mm case which is readily available. The other way to go bigger is to use a rebated case head that has the 30-06 .473 "+- bolt opening with a bigger diameter powder chamber diameter. If you want to open the Bolt face a bit to say .535 up from .474 then you can use the Ruger Short magnum cases and go all the way to the .375 Ruger in the .30-06 length action. .404 Jeffery is .445 bolt opening and the belted Magnums .555 bolt opening . So what I am saying is unless you want to open or replace the bolt head, as you can do in a Savage for a bigger diameter I'd stick with the 9.3 mm which handily takes bullets up to 300 grains and is a fine, available round. Also you don't have to mess with the magazine follower and opening to get it to feed like you would going bigger