I had a good site but can't seem to find it now. If I find it, I'll let you know. For now, though, I'll give you my understanding of your markings from my old notes. I'm not an expert in this and I am sure there are more knowledgable people out there who will correct me if I am in error (please).
First, the 6.51 with the 2-9 and the 6.46 with the 7-9 represents a range of bore diameters ranging from 6.46 to 6.59. The mark over the 2 following the 6.51 represents a bore measurement of 6.52. The pie shaped 1 2 3 is a visible rust inspection mark with 1 being the best and 3 the worst (Good to see the 1 marked here). Finally the torped marking represents the m/41 139 grn bullet and the overslag means over shooting. STR stand for streck which translates into .1 m/100 m. Therefore, if shooting the 139 grn ammo, the rifle was measured to be dead on at 100 m. If the 0 had been a 1 for instance, it would have measured .1 m high at 100 m with the 138 grn ammo. So you have a 6.52 barrel with minimal rust at inspection that shoots dead on +/-.5 m at 100 meters. I hope this is helpful and not too much in error.
First, the 6.51 with the 2-9 and the 6.46 with the 7-9 represents a range of bore diameters ranging from 6.46 to 6.59. The mark over the 2 following the 6.51 represents a bore measurement of 6.52. The pie shaped 1 2 3 is a visible rust inspection mark with 1 being the best and 3 the worst (Good to see the 1 marked here). Finally the torped marking represents the m/41 139 grn bullet and the overslag means over shooting. STR stand for streck which translates into .1 m/100 m. Therefore, if shooting the 139 grn ammo, the rifle was measured to be dead on at 100 m. If the 0 had been a 1 for instance, it would have measured .1 m high at 100 m with the 138 grn ammo. So you have a 6.52 barrel with minimal rust at inspection that shoots dead on +/-.5 m at 100 meters. I hope this is helpful and not too much in error.
