Items you will need
Tripod or other stabilizing structure
Bow target and backstop
Range finder (or a pre-measured range)
Tools for adjusting sight (typically a flat-head screwdriver, a small coin or an Allen wrench)
With considerations such as range, wind and velocity playing larger roles, sighting in a crossbow isn't exactly like sighting in a rifle. Weather conditions are in constant flux, so likely you'll be sighting in your bow every time you take it outside. Red dot sights (also known as laser sights) make this task less complicated.
Determine the conditions under which you will use your crossbow. Find out what the wind speed and direction are likely to be, as well as whether precipitation is expected. You also need to know the approximate range at which you will be shooting.
Prepare your shooting range to match the target conditions as closely as possible. Wind and weather are not always easy to accommodate, but with practice, you can learn to allow for them. Place the target at the far end of the range with a suitable backstop, then set up the tripod or brace at the desired target range.
Sight along the arrow groove on the crossbow and adjust your laser sight to match where you expect the bolt to go. Try to allow for arrow drop.
Lock your bow into the brace and fire a bolt with the red dot on the center of the target. Leave the bow locked in place and make a note of how far off center the bolt is on both the horizontal and vertical axes. Use these notes to adjust the sight according to the manufacturer's handbook, then fire another arrow. Repeat until the bolts start forming an acceptable pattern around the red dot.
Adjust your sights in small steps. Two or three "clicks" in the right direction will typically help more than five or 10.
Laser sights are simple to use, but they require occasional maintenance. Refer to your manual for care tips and maintenance procedures.
The greater the range, the greater the difference a single click of adjustment will make.
Most crossbows have a maximum effective range, usually based on their draw weight.
Arrows typically follow an elongated arc flight path, meaning they rise somewhat before they begin to fall. Take this into consideration when making your initial adjustments.
Practice with the same kind of arrow tips you plan to use, whether in competition or while hunting.
Never point a crossbow (or any other projectile weapon) at another person, loaded or otherwise.
Never dry-fire a bow. Dry firing is when a bow is fired without an arrow on the string. Doing so can break the string and possibly even the arms of the bow itself, causing serious personal injury.
Never look directly into the beam of a laser. Doing so can cause serious eye damage.
Hay bales and Styrofoam blocks are not suitable backstops, as they typically cannot stop a crossbow bolt. Use a dedicated archery or firearms backstop if possible, and always pay attention to what's behind the target.
When using a brace, make certain nothing is in the path of the bow string. This includes your fingers.
- Target for crossbow shooting. Amateur competitions. image by Igor Zhorov from Fotolia.com