This is something that even long-time archers can struggle with and getting a grasp on it when you’re just starting will not only improve your abilities as an archer but will save you countless headaches (and potentially a good deal of money) down the road. Choosing the arrows that are correct for you and the bow you’re using is a little more art than science, but there are methods to help you along the way.
The primary thing you want to be concerned with during arrow selection is the spine. Spine, and specifically “static spine,” is a measure of how stiff the arrow shaft is which determines, in part, how willing the arrow shaft is to bend during flight. Typically a shaft that is too stiff, or has too much spine, will tend to land left of where you are aiming (on right-handed bows) and shafts that are too weak, or have too little spine, tend to land to the right of where you’re aiming (again on right-handed bows). Finding arrows that fall right in the middle of these two extremes is a process of balancing three different factors; static spine, length, and point mass, which when combined determine your “dynamic spine.”
Quickly let’s go over the difference between “static” and “dynamic” spine. Static spine is the measure of an arrow shaft’s spine during its creation, typically measured with a spine tester. This measure does not take into account the effect of arrow length or point mass on spine. Dynamic spine, on the other hand, is a measure of an arrow’s spine while in flight and does take into account the effect of arrow length and point mass on the spine of the arrow. Dynamic spine is what we’re ultimately looking for when we’re trying to balance static spine, arrow length, and point mass. This process is often referred to as “tuning.”
The next thing to consider in arrow selection is arrow length. The longer an arrow is, the weaker its dynamic spine will be. Unless you’re making your own arrows, you likely won’t be cutting the arrow shafts yourself so a good rule of thumb is to make sure your arrows are at least 1 inch longer than your draw length (if you don’t know how to determine your draw length two different methods are detailed here). For adjusting arrow length beyond the minimum length required (which again is your draw length plus 1 inch), just understand the relationship between length and dynamic spine and err toward higher spine ratings for longer arrows (unless of course that is not balanced for you, in which case you should adjust accordingly).
Finally, when determining dynamic spine we must consider point mass. Point mass (sometimes referred to as point weight) is a measure of the mass of your arrow tip (which is not included in the arrows length). This is typically a field point or broadhead that is secured in some fashion to the end of your arrow and in the case of commercially available ones, will have a mass in grains listed on the package. If you’re making your own arrow heads you can weigh them on a grain scale to find out their mass. Point mass plays into dynamic spine by increasing the resistance to movement at the front of the arrow. To boil that down, the higher grain point you use, the weaker the dynamic spine will be. Broadhead mass also plays a role in penetration and stopping power, so quite frequently hunters will use extremely heavy points and balance the other two factors around their broadheads, instead of doing things the other way around.
So for those just getting into archery, the easiest and cheapest option for finding the right arrows for you is to get arrows with a length at least 1 inch more than your draw length, with a static spine appropriate for that length and test different broadheads or field points to find an appropriately massive point that balances the other two factors.
Quickly I will toss in one final note for those using traditional bows or self-bows; the best fletching option for these types of bows is feathers. Feathers are gentle when passing over the risers of these bows (and your hands and fingers), whereas plastic vanes will not give way and thus will damage the riser of the bow, cut your hand, and have a noticeable impact on your aim.
Research for this article was conducted at the following sites:
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