The 9.5x57 Mannlicher Schoenauer caliber was introduced in 1910 for the M-1910 M-S rifle. It was primarily considered an African game cartridge at the time. It was the last proprietary cartridge introduced by M-S (although some consider the .376 Styer one) and one of their largest.

The 9.5x57 MS is also known as the 9.5x56 MS, 9.5x56.7 MS, and the .375 Rimless Nitro Express x 2-1/4". Records show the factory cartridge as launching a 270gr bullet at between 2,150fps and 2,250fps.

The cartridge was not considered adequate for the "Big 5" in Africa, it was well liked for thin skinned, but dangerous game, including the lion. This may be because of the quick handling characteristics of the gun it was chambered in. The M-1910 is short, light, and quick handling. The stock sights are outstanding for short-range "snap" shooting.

9.5x57 MS brass is available (at this writing) from Horneber and from Bertram. However, it is the easiest cartridge I have ever reformed and can be fashioned from a variety of easy to obtain and inexpensive cases (such as the 30-06, .35 Whelen, 8x57 Mauser, 9.3x57 Norma, and several other cases). The cartridge is chambered in a gun that normally weighs between 6-1/4# and 6-1/2# so the recoil is noticeable. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.