In short, this is a one-off gun made or completed in Izhevsk in 1945. Problem is, this boxlock action doesn't look like anything produced in Izhevsk before or after. The question is, basically, whether it's an all original design or someone picked up an action made somewhere else and finished that.
The owner had it restored recently but failed to take pictures of a disassembled action.
The making of shotguns in Izhevsk was halted in June 1941 for obvious reasons and resumed in 1944, but the guns made from 1944 to 1949 were sidelocks made on prewar "B" action. The boxlocks made later on were a copy of Sauer Model 8 - again, nothing like this.
