They kept the hex reciever until 1936 I believe. I have a 1934 91/30 and it still has the hex reciever.
The round receiver was fielded by the Reds as a means of simplifying and cutting on the number of operations to get a finished receiver.
But, being hard pressed to rearm their soldiers, they made use of every available receiver they still had in arsenal.
Sometimes they defaced the Czar's crest on the receiver, sometimes they didn't take or didn't have the time to do it.
The Finn, being a very small neighbor to the big Red Russian Bear, decided that using the same weapons as their most evident foe was the best solution: at least, they could use their enemy's ammo and forget about supply lines in a pinch.
But they always strived to make their rifles better than their adversaries: they tuned the actions, shimmed the stock/receiver's contact points and exchanged Russian stocks for a practical warp-free two-piece design made of arctic birch, better adapted to the rigorous conditions of their winter and more economical to produce.
They modified rear sights to read in meters and allow for better 100 meter shooting and the up-close fighting their forest land guaranteed.
On the M-91/30, they quickly replaced the clogging-prone protected front sight by an exposed triangular blade. Truth is, a Finn Mosin-Nagant is a real fighting rifle and, most of the time, it has seen the elephant.
All this to tell you one thing: when you discover an old, tired and ugly Finn Mosin, try to read its story then clean it and go to the range.
You might be in for a surprise!
PP.
