Hi Andrey,
I seem to be having the same problem with the gamers gate version (apr 15a). I'm using the commander's sight, and scrolling the mouse wheel until the double images become one image and then firing (commander has control) and the heat round is landing very short. The sabot round impacts correctly.
I can confirm this is also happening with the Steam 2597 version, .. when I Fire from the Commander's position. I have to add about 300 yards range, which misaligns the Target, .. but, at least I can hit it with HEAT. Even SABOT seems a little low for me as well, .. I have to add a few yards to compensate.
Yesterday, as per my earlier posts, .. I couldn't hit anything, .. from the Gunner's position. A small update yesterday fixed that problem. I didn't try firing from the Commander's position.
I haven't updated my GG version to Apr15a version yet, .. still using Apr15. Firing from the Commander's or the Gunner's positions work fine.
Cheers
Tom