There are more choices in crossbow arrows today than there ever has been. When I first started hunting with a horizontal bow over 20 years ago, we had one choice in an arrow which was aluminum. Depending on what manufacturer your bow was, you could either shoot a flat crossbow nock or had to shoot a moon nock. Today we have many choices in arrows, and in recent years, the crossbow nock has evolved leaving us with more choices than ever before. We still have the flat nock and the moon nock. But today we also have a capture style nock which encompasses the string much like the arrow nock found on a vertical bow. We also have a new nock which is sort of a hybrid crossbow nock, a combination between the flat and moon nock. A common question I get asked by new crossbow hunters is if it is ok to shoot a different style of crossbow nock from their particular bow, other than the type specified by the manufacturer. So I thought it would be a good idea to explain the difference between the four types of crossbow nocks and and then discuss the golden rule when it comes to being able to shoot them from a particular bow.
The first type of crossbow nock and the one that’s been around the longest is the flat nock. Just as it sounds, this nock has a flat back. They can be manufactured from plastic or aluminum. The one main advantage of a flat nock over other types of nocks is that you cannot load an arrow that has a flat nock the wrong way.
The moon nock, or sometimes called the half moon nock, is the second most popular style of crossbow nock. Moon nocks have a crescent shape or rounded groove on the back of the nock. The groove is indexed so that it runs perpendicular to the vane of the arrow that points downward and rides in the rail of the crossbow. These types of nocks can also be made out of plastic or aluminum. But unlike the flat crossbow nock, the moon nock must be loaded the same way every time or you can risk serious damage to your bow.
The third style of crossbow nock is a capture type nock. Just like the moon nock, the are indexed to align with one particular vane on the arrow. They also can only be loaded one way like the moon nock in order to prevent damage to your crossbow. The difference in the capture style nock is in the depth of the groove. As mentioned in the first paragraph, the capture nock has a much deeper groove, similar to that of a vertical bows arrow nock. The groove is wider though to accommodate the extra thickness of a crossbow string. Some capture style crossbow nocks click onto the string and other just encompass the string.
The last style and also the latest in design is what I would call a hybrid crossbow nock. This type of nock is sort of like a moon nock, but instead of having just one groove in the back of it, it has three grooves manufactured into it spaced 120 degrees apart just like the fletching on your arrow. What this allows you to do is now shoot a moon nock, but also give you the freedom to load the arrow in any orientation you feel, without the worry of damaging the crossbow.
So now that we are familiar with the different types of crossbow nocks, we can discuss the golden rule when it comes to shooting them from a crossbow. The rule is as follows. You can shoot any of the above mention nocks from any crossbow that requires flat nocks without risking damage to the bow. You can shoot a capture nock or hybrid style crossbow nock from any crossbow that requires moon nocks, but you cannot shoot flat nocks. You cannot shoot any other style of crossbow nock other than a capture nock if that is what your manufacturer specifies to use.
So now you know the rule about shooting the different types of nocks. The next question should be, why would you shoot another type other than what your manufacturer specifies? The answer is, you really shouldn’t. But, if for some reason you find yourself on a hunt and you have to run to the local sporting goods store for some reason to replace arrows and they only have a certain type, or your at the range and your buddy forgets to bring his arrows and wants to barrow some of yours, you’ll now have the knowledge to know which ones you can and can’t use.