A three hundred yard zero is very close to mechanical zero. A 700 yard zero, obviously, less so.
What I was getting at is there aren't enough "clicks" on a Leupold scope to compensate for such a distant shot, and even if it did that many clicks would put the scope at its least accurate setting. That means the sniper had to "hold over," that is, estimate how far below the crosshairs he needed to sight to make his shot.
Yup, gotta love those mil dots eh?