The 8mm round is considerably less accurate than the 7.62x54R round.
Even though it is commonly referred to as "8mm Mauser", it was actually designed by in 1888 by a military commission and Paul Mauser had nothing whatsoever to do with it. The 8mm round literally falls out of the sky (with considerable vertical string at any distance over 200 meters) if fired from a rifle with barrel-length of less than 29" (like the Persian or Turkish mausers have).
If you want anything near as accurate as a M39, you will have to go with the 6.5x55 (Swedish), 7.65x54 (Argentine), or 7x57 cartridges (all of them true Paul Mauser designs). The Swedish mauser is the best of the lot (still supersonic at 1000 meters if fired in a true M96 and (like the M39) has won numerous military high-power competitions.
The 7.5x55 Schmidt-Rubin is also a fantastically accurate cartrige, and those rifles (the 1911 and K31) have the best trigger of any milsurp rifle.
The 98k (with its 22" barrel) has much more felt recoil than any of the above calibers (especially if fired in the prone position, which can literally break your face open with the stock if not held absolutely correct).
M39 beats the fuck out of the K98.
