Idmay375,
It's hard to find much advantage over the standard case chamberings. The 338 win mag is legendary and highly regarded. But a four or five down 338-06 carbine will be lighter, easier to carry, less recoil, and more efficient with a shorter barrel. I've chronographed factory loads in the 20 inch 338 win mag guide gun, the loads are within 70-80 fps of your hand loads.
Same with the 9.3x62 mauser. I had both the 375 ruger and a five-down cz 9.3x62 carbine. The 9.3 stayed, but the 375 ruger found a new home. 300 grain bullets at 2460 fps ain't no slouch.
In a way, the standard case medium bores are a serious contender against the magnums. Hand me a 9.3x62, 35 whelen or 338-06 on a running or wounded animal, I guarantee that I'll get more aimed shots out the barrel, over the magnums.
Even up to 41 caliber on the standard case (technically still a medium bore):
My 41 wildcat off the 9.3x62 case, it was a lighter, shorter gun that held 4 rounds down over my 416 ruger. The recovery from recoil was quicker as well.
When standard type B mauser rifles were exported to Africa in the early 1900's it was a sufficient dangerous game gun affordable to bush people. They were stamped 9.3x62 mauser or 10.75x68 mauser.
The magnum mausers went to custom gunmakers aimed at a wealthier crowd.
Our American 35 whelen, 333 OKH and 400 whelens were essentially the working man's versions that accomplished the same thing that the 10.75x68 and 9.3x62 did in Africa.
But what do I know, i poop in a hole and have no electricity or running water.
But you do have internet 👍
