The thing that causes problems is that the game is very selective about what realistic (if exaggerated) mechanics it acknowledges: It has the progressively worse drop, but the bullet velocity is always constant, which is sort of a mindf**k.
EDIT: Apparently my data about this is off. See Respawn response below. (The point from the rest of my comment stands, although I am now unsure of what exactly is the culprit.)
This also leads to the rather insane case where you have to lead people who are no more than a few meters away from you with shotguns and SMGs, because instead of having their bullets start out fast and rapidly lose speed over distance, the game averages the two extremes and has them move like softballs all the time.