Shooters tend to blame the bow, the scope, or both when having difficulty getting their crossbows dialed in. But today’s bows and optics are so well designed and constructed that nine times out of 10 a zeroing issue rests with the person pulling the trigger.
With that in mind, here are some tips that will make zeroing-in your crossbow a lot less frustrating.
1. Stop everything and read
I’ll start off by suggesting that every crossbow should have a scope. It will simply make life at the range and in the field easier. But you do have choices — lots of them.
Whatever make and model you chose, it is vital to understand how it works and to follow the manufacturer’s instructions during setup and sighting-in. The owner’s manual is your bible.
Read it and study it until you know it inside and out. This is especially important for scopes having a speed ring, which can vary slightly from manufacturer to manufacturer and tend to be confusing.
Bottom line, it is next to impossible to achieve consistent zeroing-in until you fully understand all of the features of your scope.
2. Properly mount your scope
This might sound rather foolish, but it is surprising how many crossbows and scopes are not properly mated, particularly scopes with multiple crosshairs. Without proper eye relief and ensuring the scope crosshairs are perfectly parallel with the crossbow, consistent accuracy cannot be achieved.
After thoroughly reading the scope manufacturer’s owner’s manual, secure the bow in a padded vice, making sure it is level side-to-side by placing a small carpenter’s level perpendicular across the flight rails and adjusting as needed.
Once it’s level, carefully tighten the bow in the vice. After securely attaching the base mount (if any), fasten the bottom half of the scope rings to the base. This provides a solid foundation to work from.
Next, place the scope in the bottom rings and attach the top half of the rings, snugging them down just enough so the scope can be moved back and forth and rotated from side to side. To attain proper eye relief, look through the scope and adjust it back and forth till you get the best image.
The next step is to make sure the crosshairs are parallel to the bow. Do this by placing the carpenter’s level on top of the elevation adjustment knob cap, gently rotating the scope in its rings until level.
Carefully check the eye relief again and tighten the scope ring screws to the manufacturer’s specs. The key here is to snug each screw evenly, with the same half or quarter rate of turn, until all of the screws are tight. Doing so applies even pressure on the scope tube and keeps the crosshairs parallel to the bow, eliminating the possibility of the scope canting.
3. Maintaining zero
Nothing lasts forever, and while a scope should hold zero for quite some time, things can change. This is especially true during hunting season when bows are susceptible to bumps while walking into hunting areas or being roped into a tree stand, dropped due to cold hands, or rattled around in the truck or ATV.
As a matter of course, it always pays to check the zero on a weekly basis during the hunting season and especially before the season opener after months of storage. The chances are good that nothing has changed, but it’s important to make sure. Other than making sure the lenses are clean, crossbow scopes don’t really call for any maintenance, but the bows themselves do.
Dirty rails, strings, and cables not properly tended per manufacturer’s instructions, dirty trigger mechanisms, and compound models not properly tuned can affect accuracy. Take care of your bow, and it will take care of you.
4. Initial Zeroing-In
Sighting-in a crossbow with a multi-reticle scope, isn’t difficult. The manufacturer’s guidelines in the owner’s manual are nearly always sufficient, and I have found the same method used for a rifle or muzzleloader works well with a crossbow.
Following the manufacturer’s guidelines, generally start off at 20 yards and use the arrows that came with the bow or other arrows recommended for your specific bow that you plan to hunt with.
Shoot from a stationary platform rather than off-hand. Personally, I prefer to use a solid base, such as a Lead Sled or other shooting rest. Most are designed for firearms, but they work well with crossbows, too.
Securely placing the bow on sandbags also works. The important thing is to have a solid platform. Once this is done, take a shot at 20 yards. Then, with the crosshairs on the bulls-eye and without moving the bow, simply adjust the windage and elevation turrets until the 20-yard crosshairs center where the arrow hit.
This should align the bow and the scope and get you pretty well zeroed-in. Some additional shots and fine-tuning might be necessary by adjusting windage and elevation a click or two, but you should be on the money at 20 yards and out to 30 and even 40 yards using the appropriate crosshairs.
5. Standardize shooting techniques and practice
It’s important to keep in mind that crossbows are much more sensitive to adjustment or inconsistencies during the shooting process, no matter how minute, than rifles. Given that, consistent accuracy hinges on developing good shooting techniques.
The place to do that is at the range, and it will prove crucial while hunting. This means everything from cocking the bow evenly to keeping the bow level while shooting, making sure to squeeze and not pull the trigger, to following through after the shot.
The only way to develop proper shooting mechanics is by practicing and practicing some more, every chance you get until shooting your bow becomes second nature.
Three things are critical at the range but especially important in the woods — proper cocking, the proper release of the arrow, and keeping the bow level during the whole process, whether shooting from the ground or an elevated stand.
There was a time when cocking ropes were rather basic, and some still are. But those shipped with most new bows are now equipped with pulleys or some other guiding device that not only make the cocking process much easier but keep the string and serving equal on both sides of the rail right into the trigger mechanism.
Most bow manufacturers offer upgrades, and several aftermarket cocking ropes that keep the severing properly aligned are available. Some bows are equipped with an integrated cocking mechanism that works well and are easy to use.
Mechanical cocking devices also work well, although can be somewhat cumbersome to use, especially in the field. Overall, developing proper and consistent shooting mechanics is pretty much up to the shooter.
The more time spent shooting the more developed these skills become. This is especially true when it comes to triggering the bow. Today’s crossbows come with various trigger pulls, some as light as 2 pounds, others as much as 4 or even 5 pounds, and varying degrees of travel, or creep, from hardly any to considerable.
On most bows neither is adjustable, but whatever the case it is important to know the amount of pressure and creep it takes to discharge the bow. This can be achieved only by shooting the bow repeatedly at the range.
The same is true of cantering, which is basically allowing one limb to dip lower than the other. Depending on the range, a slight canter can throw an arrow off several inches, and it is impossible to sight-in a crossbow properly if cantering persists.
Cantering often happens subconsciously, especially during the excitement of the hunt, often from elevated stands where twisting the upper body is sometimes required to make a shot.
In doing so, the bow has a natural tendency to canter. But if the scope is properly mounted, the crosshairs can be used as a reference to keep the bow level when shooting. Again, it takes practice, ideally from an elevated position, if you plan to hunt from a tree stand.
6. Practice with the arrows you hunt with
I mentioned this briefly, but to achieve and maintain the best accuracy, crossbows are no different from vertical bows in that they perform best with the proper arrows. Most crossbows are purchased as kits, with arrows matched to accommodate the bow’s draw weight and to optimize speed and accuracy.
In general, this means arrows that are the proper size in diameter, wall thickness, construction material and stiffness, arrow length, weight, and front-of-center balance point, or FOC.
Deviating from any of these specifications can have a drastic effect on a crossbow’s efficiency and point of impact because the amount of energy to release the arrow might be more or less than what the bow calls for, thus affecting arrow speed, which in turn affects accuracy.
Use only the arrows specifically recommended by the manufacturer, and if unsure, check with the manufacturer directly, visit its website or read the owner’s manual to make sure.
Now, this doesn’t mean that today’s crossbows won’t or can’t shoot heavier or even lighter arrows than what comes with a given bow or what is primarily recommended.
They will and do quite efficiently, and in fact, most manufacturers provide a shortlist of recommended arrows in terms of weight and length for different types of game. But when they do, they also generally indicate a change in energy and speed, and in some cases, a change in trajectory and arrow drop at various ranges.
Keep in mind that if you change arrows re-zeroing your bow might be necessary.
7. Practice with the broadheads you hunt with
The same is true of field points, expandable broadheads, and fixed broadheads. Contrary to common belief, field points don’t always fly the same as expandable broadheads and certainly not the same as fixed broadheads.
Field points and expandable heads are close, perhaps close enough within acceptable crossbow range for some hunters. But the same heads you plan to hunt with should be used during initial sighting-in to get a true zero.
Even though a 100-grain field point might weigh the same as a 100-grain fixed blade or expandable, their difference in length might alter the arrow’s FOC. The arrow might also flex and recover differently or have a longer or shorter trajectory, and either factor can affect point of impact from that of a field point.
Fortunately, many broadhead manufacturers understand this and supply a practice head of the same design and weight as the hunting heads.
Generally, the only difference is in color to denote the practice head from its hunting counterparts. If not, considering most fixed and expandable blades can be re-honed to sharpness or fitted with new blades, it is worth the sacrifice of one “practice head” while zeroing-in.
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