It is not known exactly when the 9,3x57 was designed, but it dates back to the years around 1900. It is nothing but the 8x57 opened up to accept .366” bullets. This cartridge is very similar to the 9x57 Mauser (.358” bullet) and the 9,5x57 Mannlicher which has a differently shaped case. There is also a 9,3x57R with a straight case.
The only surviving of these cartridges, however, is the 9,3x57 which in Scandinavia still is used for hunting driven moose and lesser game - very often in Husquarna bolt action rifles. The 9,3x57 is nicknamed “The Potato Thrower” due to its heavy bullets and rainbow-like trajectory. It is probably going to be around for a good many years to come, but it is a dying caliber, as no manufacturer makes rifles in this caliber anymore.