IIRC, Mauser bottom metal sizes are sorted by action length - so, if your action's a .30-06 length, the standard parts for a large ring M-98 will fit.
If it's a shorter action length, say .308 length - the standard-sized parts will be too long between guard screws.
The magnum actions (.375 H&H, etc - usually a square bridge) are longer between the guard screws than the .30-06 length.
I would measure the distance between the guard screws on your gun, and give any supplier a call for a match.