Originally Posted by Mongo
My brother shoots one. He thinks the accuracy is due to the 29" barrel. I prefer my FN 7x57 mauser.
The following may also explain accuracy:
There is a brass disc about 30mm in diameter inletted into the right side of the buttstock. There are actually three disc variations, an early 2-screw disc, a later 2-screw disc, and a 1-screw disc. My rifle has the one screw type disc, and the information that follows pertains only to the one screw disc. For information about the two screw discs, or additional details about the one screw disc and lots of other information about Swedish weapons, see Mats' Weapons Page online. That is where I learned how to decipher the disc on my rifle.
The one screw disc is divided into 3 sections, each of which is marked in such a way as to reveal some information about that particular rifle. The smallest "slice" of the brass disc bears the numbers 1, 2, and 3 with a triangular punch mark over one of the numbers. This indicates the condition of the bore. No punch mark is perfect. 1 means a very few dark areas in the corners of the lands and grooves. 2 indicates rust in the corners of the lands and grooves and possible light rust in the grooves. 3 indicates spots of light rust throughout the grooves, but no sharp edges; this is still acceptable. A rifle scoring lower than 3 was rebarreled. My rifle is a 3, but any rifle passed by the Swedish armorers will shoot very well, as the inspectors were quite picky. The bore of my rifle looks good to the naked eye.
The next slice of the little brass disc indicates the elevation aiming error when shooting the standard m/41 Swedish service load, which used a 140 grain boat-tail spitzer bullet at a MV of around 800 m/s. There are three Swedish words in this sector of the disc. "Torped" indicates the 140 grain BT spitzer bullet (there was an earlier 156 grain RN bullet), "Overslag" means over, followed by a space and then "Str." Str is the abbreviation for streck, a unit of angle, and there are 6300 streck to a circle. Streck were used in a manner similar to the way North American shooters use minutes of angle. If there is a number in the blank space between Overslag and Str. it indicates the amount the rifle shoots over in terms of streck. 1 streck equals approximately 1/10 meter at 100 meters. So a 1 in the space on the disc indicates that rifle would shoot 10 cm (or a little less than 4") above the point of aim at 100 meters. The space is blank on my rifle's disc, indicating that it shoots to point of aim.
The largest slice of the disc has an outer and an inner arc of numbers. The outer arc bears numbers "6.51" followed by the numbers 2,3,4,5,6,7,8,9 (my rifle has a punch mark over the "2"). The inner arc bears the numbers "6.46" followed by 7,8,9,0 (no punch mark over a number in the inner arc on my rifle). It is my understanding that these numbers reveal the nominal bore (6.46mm) and groove (6.51mm) diameters of a new barrel. The punch mark(s) reveals the actual diameter of the particular barrel (and thus, presumably, any wear). Thus, my barrel has a groove diameter of 6.52mm. Apparently the bore diameter of my barrel measured right at 6.46mm.
If the groove diameter measures between 6.51mm and 6.53mm all was well. If the groove diameter measured 6.54mm-6.55mm the rifle was used only for training. If the groove diameter exceeded 6.56mm the rifle was rebarreled. The Swedes are very meticulous people!
( Pulled from an on-line source )