When arrows are released, two things immediately occur that impact accuracy. The first is that the act of shooting causes the arrow to sway or wobble in the air.
For those who shoot fingers-only, that sway is on a horizontal plane and is referred to as "wallowing." For release-shooters, the sway occurs in an up-and-down manner on a vertical plane and is called "porpoising."
At the same time, the arrow itself is also bending and flexing back and forth. The arrow spine is the measure of the amount of bend in an arrow shaft when weight is placed at the center of a shaft supported on both ends — basically, how stiff it is. Wall thickness, diameter and length, as well as the weight of the head, define spine.
Generally speaking, with the arrow both bending and swaying when released, the faster both are stabilized the more accurate the shot. That's why arrow companies offer shaft selection charts.
Each type of bow design, draw weight, draw length, head weight and arrow length combination has its own sweet spot for balancing arrow bend and sway to achieve the most accurate flight. Here are some other need-to-know facts about arrow accuracy.
ACCURATE ARROW DIAMETER
A few years ago, Easton introduced small-diameter shafts. Just as a mechanical broadhead does not catch as much wind, a smaller-diameter arrow also has a reduced profile and flies better than a full-size arrow in a crosswind.
And because the shaft is smaller, there is less friction during penetration. The arrow will go deeper and do more tissue damage. These arrows are worth looking into if you haven't yet.
The last component in all of this is arrow speed. The faster the arrow the less it drops in flight and the quicker it reaches the animal. At the same time, the more "touchy" that shooting form, bow tuning and arrow flight all become.
Though speed is determined predominantly by the bow, lighter and smaller diameter arrows fly faster than heavy arrows. The catch is that the lighter arrow weight packs less kinetic energy.
THE SPIN TEST
It's up to each hunter to ensure proper arrow flight by spinning their arrows after the hunting heads have been attached. When placing arrows on a spinner, be sure that the shaft is straight and there's no wobble with the hunting head and nock.
Finally, practice with hunting arrows before hitting the woods. Often, there is a difference in how practice points and hunting broadheads group. If the hunting arrows are flying all over the place (assuming the shafts have been matched to the bow), the bow is tuned and the hunting arrows' spin true, it's time to look at different broadheads.