From the instant a bullet leaves the barrel, it begins to drop. How much? The only way to find out for sure is to go out with your rifle and whatever ammo you favor and shoot at 100, 200, and 300 yards.
Sight in your rifle to hit 3 inches high at 100. Then, set up a National Rifle Association 50-Yard Slow Fire Pistol Target (the one with the 8-inch-diameter bull) at 200 yards, hold right on the center, and fire five shots. You’ll probably see no drop at all. If you do, make a note of it.
Move back to 300 yards and try the same thing. If your rifle produces at least 3,000 fps, you’ll probably get a drop of 3 inches below the center of the bull. If you’re working with 2,600 to 2,850 fps, then you’ll see a drop of 6 to 8 inches from center.
When the time comes to shoot at something that’s alive, you’ll have very little to do in the way of calculation. If your bullet drops 3 or 4 inches from center, hold where you normally would, more or less on the center of the body. If the drop is 6 to 8 inches, you may or may not have to allow for it. On a big animal like an elk or a caribou, I would hold a handbreadth (4 inches) high. On something small (an antelope or a little whitetail, for example), I’d allow two handbreadths. Whatever you do, as long as you know that the range is no more than 300 yards, never hold out of the hair. Untold numbers of animals have fled from bullets whizzing over their backs.
When you’re shooting uphill or downhill, hold low. The closer to vertical a bullet flies—either high or low—the less it drops over distance. How much to hold? I can’t tell you. I can only advise that you’ll probably miss more shots by overcompensating rather than undercompensating.