Bubble gebars ;D ;D
Not really ...
Here is the CIP data for the 9.3 x 64 Brenneke
CIP 9.3 x 64 Brenneke
I do not really like it as it is a .. REBATED rim
Apparently you will find it hard to acquire brass ( cases ) but I am sure factory ammo exists
Gun-smithing is just really machining ( tool and die maker ) ANYTHING is possible
Except of course for ridiculous legislation ( and money )
Easy enough to acquire the chamber reamer ( a standard calibre ) and reloading dies
You may even be able to ream out a 9.3 x 62 to 9.3 x 64 ? ( 64mm will fit in a standard length action )
Otherwise just get a new barrel
Opening up the bolt face is a trivial exercise - for a very good machinist
I am fairly sure one could make a wildcat based off the 375 H&H - but then that would be - belted !
.375 Ruger could then be used necked down to 9.3 = .366"
The options are endless - if you are prepared for the experimental - long road