Nitro,
I still have a copy including a .pdf (23MB - not the best quality of a tattered copy I'm sorry)of Guns & ammo "Big Bore Rifles" Volume 1 No 1 1983.

Chapter 6 Imported Bolt action big bores Page 39 bottom RHS of page & I quote:-

"Left: Some of the most powerful
for calibre of metric cartridges
were developed by Brenneke and
featured his TUG and TIG bullets.
The 9.3x64mm is so powerful that
its ballistics even surpass those
of the .375 H&H mag"
End quote.

So there gents in black & white in a small note for all to see, Jack Lott himself described the 7x64, 8x64 & 9.3x64mm rounds - Wilhelm Brenneke's finest creations!
See told you!
93x64mm