After years of being the administrator of the Crossbow Nation website, I see a trend at the same time of year right before hunting season. This trend is a reoccurrence in threads being started by members complaining about their broadheads not flying or not grouping well when shot from their crossbows. The topic title usually says something like “My broadheads don’t group good out of my crossbow” or “My broadheads don’t hit in the same spot as my fieldpoints.” One thing that also seems to be consistent with these posts is that the member almost always looks to their broardheads as the problem. Many members automatically just assume that because their crossbow shoots field points well, that broardheads shot from their crossbow should shoot well too. But as we read every year on the forum, this isn’t always the case.
Broadheads can be finicky. Even with a perfectly tuned crossbow, your broadheads may not have the same point of impact as your practice points. There are some factors other than your broadheads that can be the cause of this. In this article, we’ll take a look at why some crossbows have a hard time shooting broadheads accurately, and what you can do to to get the best flight, and most consistency while shooting broadheads from your crossbow. If we take crossbow broadheads out of the equation, what else are we left with that could possibly effect your broadhead flight? The answer, your arrow and or your crossbow. Just because you shot all summer long and achieved good accuracy doesn’t mean you may not have a problem with one or maybe even both. So let’s take a look at each piece to the equation and I’ll shed some light on what might be the problem. Unfortunately, the bad news is, you may not be able to fix some of these issues. But helping you diagnose what the problem is, is the first step to being able to shoot broadheads more accurately out of your crossbow.
The first thing we’ll look at is arrows. I chose them first because they are the least expensive of the two factors that could effect broadhead flight, and if you had to change one part of the equation, arrows would be the easiest and least expensive. As I have already stated, just because your arrows group well for you with field points installed, does not mean your broadheads will fly just as good when shot from your crossbow. In most cases, they won’t. We know that most hunters automatically assume the broadhead is at fault. But in many cases, they’re not. What broadheads are guilty of is magnifying the problem areas you had all along with your arrows or crossbow that weren't as noticeable with practice points. From my experience, I have seen three common issues when it comes to crossbow arrows.
The first is the change in front of center balance as a result of the overall length of the arrow changing when screwing on a broadhead as compared to a field point. Most hunters would think that because the broadhead is the same weight as their field points that nothing has changed. But by adding the longer broadhead, the FOC does change. Only by a small amount, but it changes. When you screw on a broadhead, the center of the arrow now changes effecting where the arrow flexes and how it comes off the rail of the crossbow. Again, not by much, but it has now changed. This is why in most cases, broadheads that fly the best out of a crossbow will have a short ferrel. These sorter crossbow broadheads do not effect the FOC of the arrow as much as a broadhead with a longer ferrel. So a change in FOC can change your point of impact. However, if this were the only issue, then every arrow tipped with the same broadhead would group together, and we could just adjust a scope a few clicks and be good to go. But we all know that doesn’t happen very often. So what else could be the problem?
Arrow spine could be your next issue. The purpose of me bringing up the issue of arrow spine isn’t to determine if it is too weak or too stiff, it’s to inform you that it should be consistent from arrow to arrow. There is no more consistent factory made crossbow arrow than an aluminum crossbow arrow. So if you’re shooting aluminum crossbow arrows, this most likely isn’t going to be a cause of poor broadhead flight. Carbon crossbow arrows however, can have a significant spine variance. Many hunters may not know this, but because of the nature of how carbon crossbow arrow shafts are manufactured, the spine can vary when measured at any given point around the circumference of the arrow. Basically, it can be heavier or weaker spined from one side of the shaft to the other side. In order to get the best groups while shooting broadheads from your crossbow, having arrows that are spined matched is key. Most manufacturers do not index the spine of the arrow. At the time of this article I only know of one manufacturer that advertises they do, and one custom arrow maker advertising the same. But there are ways to test how your arrows are spined. The first way would be to buy a spine tester. I wouldn’t suggest doing so however unless you have exrta money you are willing to part with. Chances are, your can find a local archery shop that has one and would be able to index your arrows for you for a small charge. The other way, which costs the crossbow hunter nothing, is to shoot your arrows in your backyard. It will take some time, but here’s how you can super tune your arrows so that they will shoot as tight as groups as possible. Let me first point out that this should be done with field points. You can do this test with broadheads, but because you will be doing lots of shooting at the same spot, you would most likely ruin a broadhead target in one afternoon doing so. What you’ll want to do is shoot each arrow at spot on a target. Preferably at a longer distance. It could even be longer than you would ever shoot while hunting but length magnifies error, so I would say at the minimum 40 yards would be good. After shooting each arrow at a spot, take the arrows that shoot the farthest away from the centers, and rotate them 120 degrees so that the next vane in line is now your cock vane. If you are shooting a moon or capture style nock, you will have to reindex your nock before shooting the arrow to avoid a possible dry fire and damaging your crossbow. You’ll want to do this a second time so that you have a measurement shooting all three of the vanes as the cock vane, or the vane that points down into the rail of your crossbow. You should see some variance between each rotation. You want the one that is the closest to the center of the spot you were aiming at. What you are doing is indexing the spine through trial and error as opposed to having it marked for you. It could take all day, but if you do this to each arrow, you will shoot tighter groups with both field points and broadheads. Once you go back to closer ranges, you will be amazed at how tight your groups can be.
Another thing you’ll want to check is that your crossbow broadheads are all aligned in the same orientation. This doesn’t mean that they have to be aligned with your vanes. But they should match each other from arrow to arrow. If you are shooting a two or four bladed head, there would be no way to align them with the vanes anyhow. The blades of a broadhead catch the air and can cause your arrow to plane. Especially if your arrow isn’t coming out of your crossbow perfectly straight. By aligning the blades the same way on all of your arrows, if they do plane, they will all plane with some consistency.