I've never been much on cast bullets in rifles, but when I did quite a bit of casting for handguns I found many seemed to shoot better with the bullets just slightly oversized. Most other folks swore by bullets sized to the exact measurement of the grooves. But then there was different alloys and others issues to worry over.

As far as info on groove diameter, I don't take this guy's word for gospel on everything but here's Hawk's spin on it http://www.chuckhawks.com/swedish_mauser.htm

Here's another: http://www.gunnersden.com/index.htm.6-5x55-swedish-mauser.html




People tend to put value on the rifles based upon what that disk reads, but the disks are sometimes switched between rifles. Even if it is an original disk, people seem to forget that the rifle may have had thousands of rounds put through it since the last time the disk was marked!