Early 8MM's (1888) used a bullet of .318 diameter, called the Patrone 88.
The Germans redesigned it in 1905 and changed the diameter to .323 and smokeless powder, and they designated it "S-bore" or S Patrone.
Your M48 is just as strong as a K98, and uses the same ammo.
There are lots of Mauser made rifles, small ring, large ring, some made in Turkey, some in Sweeden. You can read for a month about Mausers.
8 × 57 IS
8 × 57 JS
8 × 57mm
8mm Mauser
These should all be the same round and safe in your M48.
8 x 57 I
8 x 57 IRS
These two are NOT the same round and will not work.
Our own 30-06 was redesigned from the original 30-03, the 03 Springfield, later the 03A3, and was inspired by a Mauser.
I hope this is the answer you were looking for.
I'm no expert!