Does your's look like that one? Are there any other markings on it? If it's a sporterized Mauser, Rw.E. is likely the smithy who did it long ago. Said smithy may not be alive, never mind still working.
If your's is a .318" bore too(assuming it's an 8mm at all), you can't use commercial or current milsurp ammo. It's loaded with a .323" bullet. The Germans changed the bullet and bore diameter in 1903. Your's is not likely to be a K98 if it's chambered for a .318" bullet either.
If you're not sure what it's chambered in, slug the bore by hammering a cast bullet through the barrel and measure it with a micrometer. That'll give you the bore diameter. Then you'll need to have a chamber casting done to find out what cartridge.