Make sure you really have a M-48 action and not one of the older full sized Yugo Mausers.
Intermediate Large Ring M-98 ,(Large ring, Short action)
1.410 diameter. receiver ring,
8.50 in length, with screw spacing of 7.620 inches
Intermediate Large ring have a threaded shank diameter of 1.10 in. With 12 threads per inch.
Mexicans by FN and Belgium, the M24, M47, M48 by FN and Yugoslavia.
WILL NOT fit a Standard 98 Mauser stocks and standard bolts will not interchange..
Large Ring M-98
1.410 diameter receiver ring, 8.750 in length,
with screw spacing of 7.835. Barrel Shank of 1.100
Large ring have a threaded shank diameter of 1.10 in. With 12 threads per inch.