Originally Posted by Trash
I think what you meant to was that heavier bullets are more stable and predictable at long ranges. Drop is a function of time of flight and NOT bullet weight. A slower bullet will drop more over a given distance than a faster one.
The reason for using heavier bullets is lower drag so less drop percentage is realized than lighter bullets (not less drop overall, just less of a percentage than lighter with velocity difference factored). Lower drag and VLD profile also contribute to less wind drift.