Due to increasingly more liberal regulations and an aging population with accompanying physical limitations, crossbow use has increased dramatically almost nationwide. 

The increased demand has led to many technological advances in crossbow design and accessories. The accessory that has seen the most improvement is the scope. Better optics and newer features such as variable power, illuminated reticles and ocular lens adjustments combine to make these scopes clearer and more accurate than ever.

A huge leap in technology

For many years, crossbow scopes were fixed power with multiple crosshairs.  This enabled the shooter to have multiple aiming points without resorting to “Kentucky windage” — holding over the target at longer distances. The problem was that each manufacturer only made one scope for many different crossbow models of different speeds. This led to vast differences in the corresponding distances at which each crosshair was zeroed depending on which model crossbow it was mounted on. Shooters had to learn distances through trial-and-error by shooting a lot of arrows at varying distances, often carrying a “cheat sheet” to keep track of them.

Higher-end, modern crossbow scopes, such as the Hawke Optics XB-1 that I use, allow the shooter to calibrate the crosshairs to exact, 10-yard increments, making life much simpler. This is achieved by turning the variable-power ring to adjust appearance of the gaps in the crosshairs. 

Unlike a variable-power rifle scope, where a hunter uses a higher power to examine his target better or shoot longer distances and a lower power for closer shots; once a crossbow is sighted in, the shooter never moves the variable power ring again. This is probably the most-misunderstood feature; I get more questions about it than any other crossbow topic. This week alone, I’ve had eight to 10 phone calls asking for help with this feature.

Step by step zero

First, make sure that the scope is properly mounted, level, and that all screws have been tightened on both the base and rings. Then, adjust the ocular focus ring at the back of the eyepiece until the crosshairs become clear and focused. Next adjust the variable-power ring, aka speed ring, to the published speed for your crossbow. There is no need to chronograph your crossbow; you can calibrate the scope better by shooting at two distances. Next, zero in your top (20-yard) crosshair at a measured 20 yards using the scope’s windage and elevation turret adjustments. 

It is important to remember that these adjustments are being made at only 20 yards, because most scopes are ¼- or ½-minute of angle, meaning at 20 yards it will take five clicks to move your arrow’s point of impact ¼- or ½-inch. In other words, you will be moving them a good bit more than when you zero a rifle at 100 yards. Once you have the top crosshair zeroed at 20 yards, replace the covers on the adjustment turrets, as you will not have to move them again.

Now that your top crosshair is zeroed at 20 yards, move back to 30 yards. Shoot at the bull’s-eye using the second crosshair from the top. Your arrow should impact the target in line with the bull’s-eye left to right. If it hits the bull’s-eye, you are done. If it impacts high, slightly turn the speed ring higher (counterclockwise) to lower the point of impact. If it impacts the target low, slightly turn the speed ring lower (clockwise) to raise the point of impact. Continue adjusting until the second crosshair is zeroed at 30 yards. When that’s done, you should be sighted in at all distances. Check another distance — the third crosshair at 40 yards — and if this checks out, you are done. 

 I recommend marking across the speed ring and scope tube using a paint marker so you can see if someone moves this adjustment. Do not move the speed ring again or it will throw your scope out of calibration. Once you have your scope calibrated and are using a rangefinder to range a target, there is no reason to miss.

A little time spent on the range calibrating your scope will pay dividends when the moment of truth arrives in the field. These scopes are an excellent addition to any crossbow that does not have a scope with this calibration feature. Try one out this year to improve your results a field.