You have the later, and most common, type of disk.
The 6.51 should have a 6.46 below it, but it may not. Regardless, the mark on “0” indicates a 6.50mm bore size was measured at the arsenal when the rifle was looked at. If there is more than one mark here, the larger bore size is the latest.
The bore condition is registered where you see the 1, 2, 3. The best has no mark on any of them, getting progressively worse working from none to 3. That said, the 3 is not a “bad” barrel. The Swedes did not keep bad barrels. Caveat that these marking were how things were at that point in time, not now.
Finally, “Torped Overslag 0 Str” indicates if there is overshoot above the point of aim with the updated 139gr m/41, boat-tail, bullet. If there is a number in this section it indicates the number of cm at 100m that the point of impact is above the point of aim.
Sorry I took so long to get back to you. I forgot this post was not finished. Thank you so much for the information.