How Lighted Crossbow Nocks Can Effect Point if Impact
Lighted crossbow nocks can be a really cool accessory to add to your arrows. They allow hunters to follow their arrows in flight better, and also aid in helping to find arrows that have passed through animals buried into the floor of the woods. Even if you only intend on shooting your bow at targets in your backyard, lighted crossbow nocks are just plane fun to have on your arrows. There are however some side effects to shooting lighted crossbow nocks in your arrows. None of them are anything to be too concerned about. But you should be aware that adding a lighted crossbow nock to the back of your arrow could, and most probably will, effect the point of impact at which your arrow hits. Let’s take a look at how and why.
The first and most obvious reason that a lighted crossbow nock effects arrow flight is do to its extra added weight. Most lighted nocks can way up to two or three times the weight of your factory installed nock. So by using a heavier arrow nock, you will have an overall heavier arrow. We all know that the heavier the arrow is, the slower it will shoot, changing it’s point of impact. How much it increases the overall weight of your arrow will be determined on how heavy the original nock you are replacing weighs. If your arrows currently have a plastic nock installed in them, it might weigh somewhere around ten grains or so. So adding a lighted crossbow nock that weighs around thirty grains could add twenty grains to the overall weight of your arrow. Twenty grains can be pretty substantial. You may not see a difference when shooting at twenty yards, but as you move out to longer yardages, twenty extra gains can make your arrows impact lower. Now, if you are already shooting an arrow that has an aluminum nock that weighs around twenty grains or so, adding a lighted crossbow nock may not have as much as an effect. At this point, your overall arrow weight may only change by ten grains or so. While ten grains can still make a difference. It most likely will not be noticed at close yardages. At further distances, it may effect your arrow, but maybe not even enough to make a sight adjustment.
So we know that a heavier arrow can effect the point of impact of the arrow. But what we have not yet discussed is how adding a lighted crossbow nock to the rear of your arrow effects the dynamics of your arrow. Two factors are effected by adding weight to the rear of the arrow. One is you change the arrows overall front of center balance point. The other is that you change the arrows dynamic spine.
The front of center of an arrow is a measurement in a percentage form, of how much weight your arrow has towards the front or point of the arrow from the center point of the arrow. Because crossbow arrows are shorter than vertical bow arrows, having a heavier front of center helps in stabilizing the arrow and can improve accuracy down range. When you add a lighted crossbow nock, you change the front of center point. Is it enough to change the impact point of your arrow? It can be. How much effect it can have depends on how much front of center your arrow had to begin with.
The second factor you are changing by adding a lighted crossbow nock to your arrow is the dynamic spine of the arrow. The dynamic spine of the arrow is how the arrow flexes when shot from a bow. Anytime you add weight to the front of an arrow, you weaken the spine. The opposite holds true when adding weight to the rear of the arrow. The extra weight of the lighted crossbow nock makes the overall arrow weight heavier, but at the rear of the arrow. More energy will be required to get the arrow started when the trigger is pulled. The remaining energy gets transferred to the rest of the arrow shaft, but it is now slightly less then it was without the lighted crossbow nock. As a result, the dynamic spine of your arrow has now slightly been effected. Just like the front of center example, depending on what arrow you started with, and how weak or stiff it was from the get go, will determine how much your arrows point of impact will be effected.
So what should you do? Install some lighted crossbow nocks and go shoot your bow. The only way you will find out how much lighted crossbow nocks effect your particular setup is to head out to the range and go shoot. Some bow and arrow combinations may see little if any change. Some may require you to make a small sight adjustment. Either way, you need to shoot your bow first before heading out in the woods to see of it has changed your point of impact. My goal for writing this article was to inform you that adding these nocks can effect your arrow. Hopefully I haven’t confused you or discouraged you from wanting to use a lighted crossbow nock. I truly believe that the advantages you gain by using a lighted crossbow nock by far out weigh any issues you may experience caused by their extra added weight. In most cases, a simple sight adjustment is the worst you’ll have to contend with.
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