Getting your arrows to fly true and group tightly isn’t black magic, as some seem to think. Here is what you need to know.
▶ Arrow Length
Correct arrow length is critical. For true flight, arrows must be sized to your rig. With an uncut arrow nocked, and a helper nearby, draw your bow while pointing it in a safe direction. Have your helper mark your arrow with a Sharpie 1 inch in front of where it contacts the arrow rest. This is your arrow length. Resist the temptation to mark your arrows as short as you can get them. An arrow that’s too short will drop off the rest when you draw the bow, potentially sticking its point into tender flesh or shattering the shaft when you release the string.
▶ Arrow Spine
Quite simply, arrow spine is how rigid an arrow shaft is. No more, no less. For an arrow to fly true, it must have the right amount of “flex,” or spine, for the bow. Determining proper spine is easy–arrow manufacturers have figured it out for us. To find the right arrow spine for your bow, you’ll need two numbers: (1) your bow’s draw weight in pounds, and (2) your arrow length in inches. After choosing the brand of arrow you want to shoot, visit the manufacturer’s website and input these numbers. It will tell you which arrow is right for your bow.
▶ Arrow Weight
Light arrows fly faster (more feet per second) and with a flatter trajectory than heavy arrows. But because they’re light, they have less mass than a heavier arrow, and deliver less kinetic energy to the target. Heavy arrows fly slower and drop faster. However, they deliver more punch to the target. You should strive for a happy medium. Not too light, not too heavy.
I like to use the International Bowhunting Organization’s (IBO) formula to determine the best arrow weight. This calls for 5 grains per pound of draw weight, before adding an insert or point. So if you’re shooting 65 pounds of draw weight, you’ll want a 325-grain arrow (65 x 5 = 325). That’s simple math, not black magic.
From the June/July 2012 issue of Outdoor Life magazine.