Yes, what we today all "wildcatters", like Mannlicher and Brenneke, were making the 6.5x57, 9x57, 8x64, and and 7x64 all before and during WW1. They really became mainstream factory offerings when the Treaty of V forbade the manufacture of arms in military chamberings, because they Germans had a strong militia tradition, and the fear was that they would all arm themselves with standard equipment.
WOW!!! Don't believe I've ever seen anyone call Baron Ferdinand Ritter von Mannlicher a "wildcatter" before. The fact is that the Austrian firm developed its own proprietary line of cartridges, which were not based on the Mauser offerings until the 9.5x57 of 1910 -- the 6.5x54 (1903); 9x56 (1905); and the 8x56 (1908)-- were parallel developments. (Curiously, though, 50+ year-old Kynoch 9x57 ammo will feed and function in my 9x56 Mannlicher-Schoenauer. I have just acquired some even older 9x56 ammo, will have to try it in my 9x57 Mauser.)
In any event, the 9x57 Mauser was developed in the very early 1900's for the German East Africa trade, because the farmers needed an affordable rifle that would handle African game, including the occasional lion. The 9.3x57 was developed primarily for Scandinavian use, though I understand some did make their way to the Dark Continent.
The Treaty of Versailles did lead to the 8x60, but had no effect one way or another on the rest of the story.
DN
