Here in BC, we used the 8x68S case to make a .375. Since the case has .003" gr. more capacity than the .375H&H, but 3 less than the .375 Ruger, it's just about equal to both- depending on the powder used.
Some time ago, just because, I opened us a .300 Win. Mag. to hold a .416 cast bullet, just to see what it looked like. I may even have turned off it's non-needed belt and rebated the rim to fit the .30/06 bolt of my Model 1917(Rem M30), however I didn't get around to buying the barrel before simply re-chambering it for the .30/.338, then the .300 Win. Mag., getting that shooting well then selling it to a young lad who HAD to HAVE it - $150.00 I think. The beltless, rebated rim .416 made a good looking CTG with slightly greater capacity than the .308 Norma.