Ok first thing is first, I am reasonably new to military surplus firearms. I got bit by the bug and now have two mosins and a k31. Back to the K98 I was checking outs the mausers with a friend at Dunham's. I realized that the one uggly dirt/oil encrusted mauser was one the ex-israeli 7.62 x 51 nato k-98s. I am pritty sure the guy will let me run a cleaning snake through it and take a look at bore. It didn't look bad but it was covered in grime. Well they have it listed at 300, so I am wondering about what you guys think and or would look for/ watch out for. I will be stopping buy after work tomorrow to have another look. Thanks for your time.
I can't offer an opinon as to what you should pay for a Mauser K98, but I can tell you that they are drying up. Several of the importers no longer have inexpensive shooter versions and all are becoming collectable. Part is due to the supply running out and part is due to people like you that just found military collectables. The prices have increased significantly over tha last few years. Specific collectable ones are astronomically priced (my son-in-law has a bunch of Mausers and in some cases, guns he bought only a few years ago have doubled in value).
If you like the gun and want it as a shooter and the barrel looks good then buy it regardless of the price (within reason). Keep it for years and it will increase in value but don't treat it as an investment but as a tool to enjoy your shooting.
As for barrels, the appearance often doesn't mean much. While it is great to find a shinny bore, sometimes a really good cleaning job will resurrect a dark bore but don't count on it. Sometimes even though the bore is dark the gun will still shoot with military accuracy but not bench rest accuracy. The barrel is not thorough cleaned unless you have exhausted your supply of patches and worn out a brush or two. Hundreds of passes of a tight fitting bore brush is often required initially to get down to bare metal. Don't forget to use a copper solvent as well as regular solvent. The "ex-israeli 7.62 x 51 nato (for practical purposes same as 308) k-98s" only shot non-corrosive primered ammo so you have a much better chance of getting or recovering to an excellent bore.