After examining the problem myself, I came to the conclusion that it's not the sight that's mounted too low, nor the refraction that should be, but isn't, modelled. It's also not the POV of the pilot that's mounted too high. The kernel of the problem lies in the fact that entire cockpit should be rotated for a few degrees relative to the plane (a mistake that can happen very quickly when building a plane).
As it is modelled in the original game, the pilot eyes (POV) are too
high (!), aiming through the sight nearly into own nose, sighting line going barely above the "bar". The pow (position of the eye(s)) of the pilot should be lower (!), aiming through the sight at a small angle upwards from where he is aiming now. Since the direction of the guns is modelled correctly on the external model, the only explanation is that the cockpit is not positioned correctly - it should be rotated around the gunsight for a few degrees "forward" (keeping the POW fixed in relation to external model) in regard to the external aircraft model. This would make it correct with no need for auxiliary correcting via bar deletion. Bar was there historically, but the pilot couldn't see it in normal position since it was too low. If the pilot wanted to see the bar in reality, he'd have to rise his head a bit to be able to see over the top of the instrument panes and look downwards along the nose - which is exactly how it is modelled in the sim as a "correct" position.
I hope all this babbling makes sense, unfortunately it seems I've lost the pictures about the matter.
