Great question. I lead more than not and I know the drop of my rifle as well as anyone that needs to make scope adjustments for distance. There is zero time for that. Secondly, there I the very tough exercise of determining range with your eye. The ranchers where we hunt, were masters at both and if anyone scoffs at shooting running antelope, they'd marvel at these guys. Your question though, still shows that some folks here don't question the prep for 1000+ yard shots, where, as we all know, any deflection, even from the most skilled shooter, leads to shot deviations which can easily rival the challenge of hitting a running target. If anyone thinks either are luck, then maybe it is just luck for themselves. I like how you raised the question. It does not minimize the preparation I put into my shooting.
BTW, I wrote "rolled" in my original post, because when you hit an running animal with a kill shot, it rolls. Hardly bragging. That GMX bullet did the job well.