Life’s pursuits usually boil down to a few simple rules. In shooting at distance, there are three: Make sure that when you mount your scope the horizontal crosswire is level; that when you aim, the rifle is not canted; and that you have a correct zero. This last may need some explaining. It means that when you sight in your rifle at 100 yards, or 200, that there’s nothing acting on the rifle or the bullet or your sight picture that will cause you to get a false point of impact.
For example, if you’re shooting in a breeze that’s pushing the bullet to the right, you’ll compensate for it with clicks to the left, and then forget about it. Then, when you shoot on a windless day and your bullet hits left, you’ll wonder WTF?