If I am aiming at something at 500m away and it is zeroed at 600, I have to aim down to where I can't even see the target (say 45 degrees) to hit it. If I zero at 400m (it doesn't give an option for 500), I never did manage to fire the projectile high enough to get the target. Maybe it was just a glitch or something, but having used zeroing in other games including this one's predecessors, the effect seemed a bit exaggerated.