I very much doubt that either Steyr or Westley-Richards designed the 9.5x57 Mannlicher-Schoenauer aka .375 Rimless Nitro Express from scratch! The 1904 DWM catalog shows a case called "9.4x56" (after bore diameter?). The DWM case #393 points to the mid-1890s. For use with this case the catalog shows bullet #156, a round nose fmj 9.6mm = .378" diameter of 25.7g = 396 gr! The drawing of case #393 looks just like the later 9.5x57 with a M88 base, a straight body and a steep shoulder.