My draw length is 29 inches. So, the arrows I shoot from my compound bow should be 29 inches long, right?
It’s quite common for archers to assume that draw length equals arrow length when shooting a compound bow. But it’s actually best to think of the two measurements as being related to each other but not married. Your draw length obviously will influence the length of your arrows. If you have a 30-inch draw length, you’re not going to shoot 25-inch-long arrows. They’d be too short.
But your arrows might not have to be 30 inches, either. Depending on what arrow rest you have and where you want the end of your arrow to sit on the shelf, you might be able to shoot an arrow that’s anywhere from 28.5 to 31 inches long.
At its shortest, an arrow can be just long enough to sit on your rest at full draw. That’s probably not ideal, since it leaves no wiggle room for string stretch. It can also cause clearance problems with broadheads. Some fixed-blade heads today have pretty big blades. If you have a drop-away rest that sits back toward you from the shelf a couple of inches, and you cut your arrow as short as that rest allows, it’s possible for the blades to catch the front of the shelf as you draw and as the rest rises. That’s no good.
Where your arrow rest sits in relation to the shelf determines that minimum length. If the rest sits in the middle of the shelf, you will need a longer minimum-length arrow than if the rest sits 2 inches behind the shelf.
Why would you want the shortest arrow possible? Let’s say you’re trying to get as much speed as possible out of your bow. The shorter the arrow, the less it weighs. If you’re shooting an Easton Axis 5 mm arrow in 300 spine that weighs 10.7 grains per inch, then cutting off 2 inches reduces the overall weight by just over 21 grains. That will add a few feet per second in arrow speed.
But there can be pitfalls to cutting an arrow down to the minimum length. One is that the arrow gets stiffer as it gets shorter. If you take two identical arrows and cut one to 30 inches and the other to 28, you might find the shorter one is less forgiving because it’s stiffer. That could become especially critical when shooting fixed-blade broadheads, which tend to magnify tuning issues.
The Easton spine chart recommends a spine of 250 for a 30-inch arrow shot from a bow set at 70 pounds. Cut that arrow length down to 28 inches, and the spine chart recommends a 340 spine. That’s actually two spine categories weaker than the 250.
Can an arrow be too long? Most new arrow shafts measure 32 inches before being cut, so that’s about as long of an arrow as you can shoot. Depending on your draw length, such an arrow might stick out an awful lot in front of your bow at full draw, which raises issues about clearance and maneuverability. An arrow that sticks out front obnoxiously far might bang into things in tight quarters, like a ground blind. Also, that’s extra weight that serves no purpose other than slowing down your arrow in flight.
So, what’s a happy medium? You can’t go wrong if you cut your arrow so that, at full draw, the end of the shaft is flush with the front of the riser — the side facing the target. That length will work with any rest on the market, and it will guarantee you don’t have clearance problems with fixed-blade broadheads. An arrow cut flush with the riser will work fine with expandable-blade broadheads, too. But using expandables will allow you to cut that arrow back a bit more to reduce some arrow weight, if you wish. A good rule of thumb is to cut it no shorter than the middle of the riser. At full draw, your arrow end would sit right in the middle of the shelf.
The best way to determine how long you want your arrows to be is to nock a full-length, uncut arrow and draw it back. Have a friend mark the shaft with a pen to indicate where the arrow should be cut, whether it’s just in front of the rest, in the middle of the shelf or flush with the end of the riser. Once you have an arrow marked, you can have all of your arrow shafts cut to that exact length.