This cartridge is widely used in Russia, and they are interchangeable, but the diameter of Finnish bullets 9.3 mm and Russian of 9.27 mm. Pressure of 2900 bar for the Russian and the Finnish 3100-3400, the bullet 15 grams in Russian and I dunno remember in Finnish, like 16.
In Russia, it is officially considered suitable for hunting all animals, including the largest - the walrus. But only up to a distance of 200 meters. Since the Finnish cartridge is slightly more powerful, it is suitable especially, though 'rainbow' trajectory.
This instance has a modification of the safer according to the type of the Swiss rifle Schmidt-Rubin. By the way, the Russian rifle was modernized in 1930 and also with the borrowing of the Schmidt-Rubin, but was borrowed iron-sight. The bent handle was at sniper options, so you should look at the receiver, whether on the side wall of the reciever marks from the installation of the sniper scope. However, the bolts were interchangeable.
Generally speaking, there were all sorts of improvements caused by the need to use weapons in mittens, fabric or youself. I mean ball on the handle.
And a small note: the rifle - Mosin. A rifle Nagant is quite different, she has a more complicated bolt with screws under the screwdriver, and "Association" of these two rifles in one was a mistake of some gun writers in the 60-ies. When the Mosin rifle was manufactured in American and French factories at the beginning of the last century, it was a "Mosin rifle".
P.S. By the way: due to the fact that in the First and Second world war Russia received rifle gunpowder from the United States, the main rifle gunpowder was some ordinary gunpowder of DuPont, the technology was also transferred. This powder in the USSR was called VT. Loads,, the weight of the bullets was the same with the 30-06. Finnish industry partly inherited from the Russian Empire all that was before 1918, I think, and gunpowder, too.