Unfortunately serial number won't help you in this instance. Lots of pictures would help get the process started, but the best way to determine your bore/groove size is to slug it.I have read that some early 98 Mausers had a .318 bore. If that is true short of measuring with caliper will serial number tell me anything?
It really depends on the rifle. The Germans are notorious for shooting "tight bore" and even over sized bullets. Bore/Groove diameters can vary immensely depending on a myriad of factors. If you have a particular rifle in mind, let us know, and we can provide more info.Until a couple of weeks ago I also thought that all were .323 grooved. Then I read an article by Allan Jones of Shooting Times where he mentioned that early 8MM rifles were manufactured with a smaller 'J' bore using .318 projectiles. So my confusion was sufficient to resort to this forum to educate me. I appreciate the responses. Five one thousandth of an inch doesn't seem like much until one attempts to push it down a barrel not meant for it at 43,000 PSI.
Ernie you have far more insight than I do. I simply read his question as stated.early 98 Mausers