RE: Using Leupolds Boone and Crockett reticle..?
The other thing that the chart says is that you have to shoot your rifle at those ranges, because they are sort of a +/- thing.
One way or another, they are pretty dad'gum close for the most part.
A friend using my .330 Dakota achored a Zebra at close to 550 yards using that B&C reticle. He had never taken at shot at over 250 yards in his life. He stuck the zebra well at 150, and it ran out into a flat pan.... stopped, and let his brother hit it with the rangefinder. He used the bottom reticle, and smacked it right through the pump. Luck... maybe... but it worked.