"...bullet doesn't drop at all..."
I'm sure you guys all know about 'battle sight zero" or 'point-blank range', right? That is the extreme distance from the muzzle where sight elevation is not required. In the case of the U. S. rifle, M16 (and variations), that distance is about 275 meters or so. By aiming at the waist level, a round should hit a human target out to 275 meters without any sight change. Past 275 meters, one aims at shoulder level. (Okay, it's been a while. My range memory might be off, but the principle remains.)
The same thing applies to regular hunting rifles. Once zeroed, one can hold on a deer and make a critical shot anywhere from just off the muzzle to "X" distance, depending on the round involved. The faster the bullet, the further the distance. A .30-06 shooting a 150 grain bullet will hit out to 250 yards with the bullet striking no more than four inches above or below the line of sight - aiming.
So, even though the bullet does in fact drop, the point of aim stays constant. That give rise to the impression the bullet does not drop.
And I bet he never really tried to hit a deer at a mile.