what you showing here is a Mannlicher M 88-90, the 8mm small bore conversion of the original M 86 in 11,15x58R. because the 8x50R and the 9,3x53R having a very similar rim and base diameter there is no problem for a competent gunmaker.
this old M 86 Stutzen in 11,15x58R was sold by Widforss in Stockholm