Crossbow scopes come in four variations: optical, multi-reticle optical and single or multiple red-dot. Optical scopes have a cross hatch that you see when you look through the scope. Multi-reticule optical are scopes with many fine lines through the cross hatch, which give you the ability to better estimate range and compensate for winds. Red-dot and multi-red dot scopes are powered and have, as the names suggest, either one or more dots in the sight that help in aiming. Though varying mechanisms, these sights have a similar method for adjusting and use.
Locate the adjustment mechanisms on your scope. The windage adjustment, which rotates the scope left and right, is positioned on the side of the scope. The elevation adjustment, which adjusts the scope up and down, is placed on the top.
Start at 10 yards from your target to check that the scope is properly installed. If you miss from this close, chances are the scope isn't installed right. If that is the case, make some large adjustments with the windage and elevation mechanisms until you hit the target consistantly. You'll hear a clicking sound as you turn each mechanism. Each click adjusts the impact distance of your projectile by 1/40 inch at a range of 10 yards.
Move to 20 yards from the target. Shoot three arrows in a group. You can't permanently adjust your scope until you can hit three arrows in a tight group.
Choose a base distance for your top reticle or dot. When the target is in this line or dot, it is "dead on." In most scopes, each reticle or additional dot indicates 10 yards difference in impact distance. Your base distance can be whatever you choose. Use the instructions that came with your scope to help you calculate how much distance will be changed in the impact distance by each "click" of the adjustment mechanisms. Usually, at 20 yards a single click adjusts the impact point by a quarter-inch. So if you're shooting two inches to the left of the target, you'll have to twist your windage adjustment eight times to compensate.
Continue to shoot at the target and change the windage and elevation adjustments to get closer and closer to the target. When you are consistently hitting the target, your adjustments no longer need to be used. Now shoot at targets knowing what distance the reticles or dots indicate.
- Men crossbow shooting image by Igor Zhorov from Fotolia.com