Gravity drop has always been modeled. I can't say for sure whether it's modelled properly but it seems fine, the ballistics have always seemed very realistic. You can observe your tracers drop in an arc as they travel more than several hundred yards. It was easier to notice in AH1 when tracers were much more clearly visible. The effect is more pronouced when firing from a level orientation, as opposed to steep dives or climbs. Your bullets will also lose velocity much faster if you're firing them upwards - one reason why, in a vertical head-on situation like a failed rope, it's always advantageous to be firing from above.
