By Chuck Adams
Most archery hunters know the basics of tuning a bow and arrow. I’ve written about tuning through paper in this column before, and companies like Hoyt and Easton offer directions on how to adjust and “tweak” their products. But I rarely encounter a hunter who knows the fine points of manipulating arrow configuration for perfect accuracy on targets and game.
I was inspired to write this column just two weeks ago when a friend gave me a call. He had purchased a topnotch bow and pristine aluminum/carbon composite shafts. Yet he was not satisfied with his accuracy, despite his best tuning efforts.
This fellow’s setup was typical of many that readers and acquaintances describe to me. With a perfect shooting situation — solid aim, smooth release, no wind, calm nerves — most setups perform fairly well. But consistent, easy accuracy is simply not always there. Getting tight target groups is iffy, even with fieldpoints. Heaven help you when you attach broadheads. Hitting where you aim is touchy. If you have a marginal string release, if the breeze picks up, or if you are even slightly tired or excited, all bets are off as far as accuracy is concerned.
My pal’s Full Metal Jacket arrows were the correct choice according to Easton’s Shaft Selection Chart. But when we discussed his setup and consulted the chart again, it was obvious his 400-spine FMJ’s were on the edge of being too weak (bendable). If an arrow is not stiff enough (shaft stiffness is called spine), it usually leaves the bow like a wet noodle and continues to whip back and forth or up and down throughout its flight. This hurts accuracy and robs kinetic energy.
I gave my friend several suggestions for stiffening the spine of his shafts. He had already spent money on his current dozen primo arrows, so he wanted to salvage that investment rather than buy another dozen FMJs in the next stiffer spine size (340).
As I explained to my friend, there are four main ways to alter the spine of your arrows as they leave the bow.
First, you can stiffen an arrow by making it shorter. Sometimes, a change of even a half-inch can work wonders for accuracy. The reverse is shooting a slightly longer shaft if you need to weaken the spine. Unfortunately, my friend’s arrows were already cut to length, and he could not cut them again because his inserts were already glued in place.
A second way to manipulate arrow spine is using a lighter or heavier arrowhead. The lighter the head, the less the arrow flexes as it leaves the bow. But again, my friend had already purchased a season’s worth of expensive 100-grain broadheads. Not cost-effective to switch.
Reducing broadhead weight to stiffen an arrow might not be easy or cheap, but increasing weight is. You can purchase commercial weight collars or washers that affix behind any screw-in head. This weakens an overly stiff arrow. For example, adding a few grains to a 100-grain broadhead might change touchy accuracy into consistent accuracy. Even the length of a broadhead can affect spine. The longer the head, the more leverage it exerts on the shaft as it leaves the bow. If your arrows are too stiff with a short broadhead, a longer model of the same weight might work better.
My third and fourth suggestions showed more promise for my pal.
If you attach heavier fletching to an arrow, the projectile slows down and flexes less. This has exactly the opposite effect of adding more arrowhead weight. Heavier head — weaker spine. Heavier fletching — stiffer spine. Most fletching manufacturers publish the weight of their products in grains, and you can usually find a lighter or heavier choice. Feather fletching is ultra-lightweight compared to plastic of the same size, so if you need a weaker shaft, a switch to feathers might work wonders. Feathers also provide about 50-percent more rear-end arrow drag than plastic, which helps even more to stabilize arrow flight.
My friend’s shafts were already fletched, but he could have made a change for very little money. Before doing that, he decided to try Option Number Four.
To stiffen a marginally weak arrow, all you need to do is reduce the draw weight of your bow. My buddy’s compound was set at 66 pounds, with a draw-weight adjustment range of 60 to 70 pounds. He started dropping draw weight one pound at a time.
At 63 pounds, the difference was magic. My friend was so happy he was babbling on the phone. His six-inch, 20-yard broadhead groups instantly shrank to less than two inches, and he was drilling a four-inch bull’s-eye almost every time at 40 yards. The most amazing thing, he told me, was how forgiving the setup had suddenly become.
Months earlier, we had discussed three other crucial parts of perfect arrow flight, so my friend already had those under control. But these three things bear mentioning here.
First, a serious bowhunter should spin every shaft on commercial or homemade ball-bearing rollers. If a shaft visibly wobbles anywhere along its length, it should be straightened or relegated to your “goof-around” pile. You cannot straighten all-carbon shafts, but you certainly can straighten all-aluminum or aluminum/carbon composites. A few talented bowhunters can do this by bending a shaft across the palm of the hand and re-spinning until it is straight. Most hunters are better served by a commercial shaft-straightening tool.
Second, watch arrow nocks as you spin your ammo. Some second-rate nock brands, and even a few normally good ones, will wobble on the shaft. Crooked nocks do not kill animals. They kill accuracy. If you cannot replace crooked with straight, you should reject arrows with wobbling nocks.
Finally, your broadheads must spin perfectly — just like your nocks. Most crooked heads can be manipulated by pressing the point in various directions against a block of wood. There is enough tolerance between shaft insert and broadhead threads to correct a majority of wobbles with a little effort.
In my experience, even mechanical heads fly better when they spin perfectly. There is usually a bit of blade still exposed as they fly, and the tiniest blade wobble catches air unevenly and degrades accuracy.
Some heads install more precisely than others. For example, G5’s new Striker V2 and Striker X models feature an improved lockup system that gives you a perfect spinner without muss or fuss. But in my experience, most broadhead types can become perfect spinners if you work at it.
Attention to the fine points of arrows can make or break a hunt. If your setup does not provide consistent and easy accuracy, there is definitely room for arrow improvement!