Well I certainly stirred up a hornets nest didn't I!
Yes basically there is nothing between the 9.3x64mm & the .375H&H on game; but that's why I like it so much, because it is such an efficient cartridge - & the German's always design GOOD gear!
Yes it fits into a normal length action as against the magnum length action, isn't that what everyone spruks on about?
So what if your humdinger is better than mine, snob appeal - because it is a Rigby or a H&H, hey they're beautiful works of art to me too!
Guess that's why I like the 9.3x64mm so well; because it's the 'underdog', hey I'm an Aussie that's our nature! It might be built on an old Mark X action, has a 26" barrel & set in an old Parker Hale stock. It's plain like me, nothing fancy, works hard & shoots a lot better than I can hold it.
When I started this project I was only 21, took me years to get info & work out loads because there was no loading data here or computer programmes to do this - Prowleys slide rule supposedly did this but I could never locate one. Years later Nick Harvey (gun scribe here in Oz) did a test on it & his data tops mine from memory - but as everyone knows, all rifles are different!
This is the "real" reason why I like it so much because I sorted this out myself & came up with data that actually works!
So whatever calibre floats your boat - even if its (now) a (common) .375H&H & it really interest you then go for it

My loads for the 9.3x64mm:-
Please start low & work up

293gn TUG & 72gn AR2209 - 2560fps Average
285gn Woodie & 74gn AR2209 - 2630fps Average
270gn Speer & 55gn AR2208 - 2180fps Average (reduced load - decimates pigs & deer!)

Cheers & try it before you get something that everyone has!
93x64mm