I touched on third-axis sight adjustment in a previous column, but this subject is important enough that it warrants more consideration.

Third-axis sight adjustments can have a profound effect on the outcome of western hunts where the shot distance may be long and the shot angle severe.

Third-axis sight adjustments can have a profound effect on the outcome of western hunts where the shot distance may be long and the shot angle severe. In tree stand settings, typically, the shot angle decreases as the shot distance increases--reducing the negative aspects of poor third-axis adjustment. However, even if you only shoot whitetails from a tree stand, you will see a small, but noticeable, improvement in accuracy by taking the following recommendations to heart. And if you are a western hunter hunting in steep country, these steps are mandatory.

What Is Third-Axis?
The third-axis of the sight is the rotational axis that the sight level moves on as the sight body angles either toward you or away from you at full draw. If you are holding the bow at full draw in front of you, the level should be exactly perpendicular to your line of sight. The level should not angle toward you or away from you. If it does, this slight angle will throw your bubble level off when you shoot uphill and downhill.

Assume that your sight body and therefore your level are grossly angled toward you. The end of the sight head (the side with the pin guard) is closer to your eye than the base of the sight body (where you adjust the sight pins). This is really no big deal if all your shots are on level ground because your bubble level will continue to read true.

However, if you aim upward or downward, the bubble level will deceive you. For example, if you aim sharply downward, the end of the sight body is still angled toward your eyes. Only now, your eye is above the sight since you are aiming downward. That means that the sight body is actually angled upward slightly and the bubble within your level will move toward you. Of course, being a conscientious archery hunter you are certain that you must now tip the bow slightly to your left (for a right-handed archer) in order to center the bubble again. As a result, you will shoot to the left. Now if the sight head is turned away from you, the opposite will occur and you will shoot to the right.

As you can imagine, when you shoot uphill you will see the opposite effect. If the sight body is angled in toward you, the bubble will move to your right and you will tip the bow to the right to bring it back to center, causing a miss to the right. If it is angled out away from you, you will tend to shoot to the left.

As you can see, this has the potential to cause very serious left or right misses. The farther the shot and the steeper the slope, the farther you'll miss.