First you post in Ostfront forums, not in HoS ones.
Second, I think you are not right because when you want to look through the iron sights, you have to pul the rifle up, and when you look through scope you pul the rifle down. so thats why there is difference in what you see.
But at the same time I have to agree that you are correct and you should see almost the same thing. I bet it will be an easy fix but FIRST we should find out how it realy looks like! THe easiest way is to pick a real KaR and Mosin with genuine scopes and so on put them on the bench and put a simple piece of cardboard , plywood or other obstacle right in front of the rifle. Then to the same for example at 50 meters or even 200 meters and compare results. Another guy is standing on the cardboard with a marker or a pencil and marks on the cardboard tat is 200 meters or even longer where exactly the iron sights makr
when they are centered and same thing with the scope of course when
its centered. This should be done for example at 100 meters with iron sights set at 100 meters and scope sights set at 100 meters or same thing at longer range with the apropriate sights settings
Then, you measure with a ruller the difference between the two markings that the guy did, and given the distance you used -100 meters, 200 meters or whatever and the Pitagors law for triangles you can calculate what ever you want for that triangle in the case the angle difference by the cosine theorem (or reverse function-the arc-cosine) or whatever. Simple geometry from 8 grade.....
actualy many things in PC games are done with math geometry and so on and if its done OK it will be realistic !