I can't really give you specific loads, but it might help you to know that "8x57" is the name given to the cartridge by the American association called SAAMI, and, in their wisdom, they established the American pressure standards for that cartridge. The European name for the same cartridge is 8x57IS (sometimes given as 8x57JS), as listed by the C.I.P., who set the pressure standards for Europeans. If you cruise through the ammunition listings on the PPU site, you will see that PPU lists and makes both of these - and they also use the identical bullets in each - but their 8x57 loads (presumably to SAAMI standards) are all slower than their 8x57IS loads (presumably made to C.I.P. standards).
A second point - I doubt that an FN made 1948 Mauser 98 is considered an "old" action - I think most writers are referring to the 1893 / 1895 / 1896 Mausers, or even earlier, when they fuss about "stressing" an "old" mauser. For the 8x57 in particular, the earliest had a .319 groove diameter, (the Patrone 88); the design was changed in 1903 to .323 diameter and the name was also changed to 8x57IS for that larger groove size. (Beside "8x57IS, the cartridge is also referred to as 7.92x57IS Mauser). I believe the bore size stayed the same - .311" - just the depth of the grooves were increased.