look here http://forums.nitroexpress.com/showflat.php?Cat=0&Number=206900&an=0&page=0#Post206900

its the same pattern like the 10,75x57 rifles and made in Suhl/Zella Mehlis for the swedish market between 1927 and 1939.
it was drilled and tapped for some kind of scope mount once. my Husqvarna M 46 was looking similar but a claw mount hide it now.
please dont destroy this rifle by re-barrel to the common 7x57. 98k actions are so cheap in norway!