In The Perfect Hunting Arrow – Part 1, I provided an overview of the many attributes the perfect hunting arrow must have. We determined the arrow must be small in diameter, stealthy and extremely straight.
Well, we’ve got a lot more to discuss. In fact, it’s going to take more than this column to do it.
I prefer to use a relatively heavy arrow. I want the arrow to be light enough to have a reasonably flat trajectory but heavy enough to penetrate well. The ideal arrow weight for you will depend on your draw weight and draw length.
The more kinetic energy your bow imparts to the arrow, the heavier your arrow can be while still maintaining a relatively flat flight path. My bows are usually set at around 70 pounds, and an arrow between 450 and 500 grains seems to provide the perfect balance between speed and weight. Generally speaking, I recommend choosing an arrow that weighs 6-7 grains per pound of your bow’s peak draw weight.
Though speed is not an intrinsic characteristic of an arrow, it is one of the things people bring up frequently when discussing hunting arrows. Thirty years ago, I was obsessed with speed and shot the fastest setup I could muster. However, my setups have been getting slower and slower over the past 15 years, even though I’m shooting the same draw weight I’ve always shot and the bows I’m shooting are more efficient than ever.
My impetus for shooting slower was the advent of the laser rangefinder. It’s not nearly as important to shoot a fast arrow if you know the distance to the target. There are many other good reasons to shoot slower.
“My setups have been getting slower and slower over the past 15 years, even though I’m shooting the same draw weight I’ve always shot and the bows I’m shooting are more efficient than ever.”
Your bow holds up longer (as do your joints). Your bow will be more forgiving and more accurate. And, most importantly (for me at least), your bow will be quieter. Lastly, a slower hunting arrow will maintain more kinetic energy and momentum downrange than a lighter, faster arrow.
An arrow’s intrinsic accuracy is dependent on four things: straightness of the shaft, uniformity of spine (no information is available to the public on this arrow characteristic. I use a spine-testing machine), consistency of the fletching (I fletch my own arrows to assure they are perfect, and you should too!) and consistency of weight. On my setup, one grain difference in arrow weight equates to 5⁄8-inch difference in impact point at 100 yards.
The FOC (front of center) is simply a calculation of how far the balance point of the completed arrow is away from the physical center of that arrow. It is calculated as a percentage of total arrow length. If your hunting arrow were to balance dead center, with half the arrow shaft in front of the balance point and half of the shaft behind the balance point, the FOC would be zero. If the balance point is three inches in front of the center of the shaft on a 30-inch arrow, the FOC will be 10 percent.
The heavier the point weight, the higher the FOC. I like to have a high FOC for a couple reasons. I believe a higher FOC makes the arrow penetrate better, and it also makes my arrows group better. So, if you’re going to add weight to the arrow, add it to the front.
Another way to increase the arrow’s FOC is to use small, light fletching. Any weight taken off the back of the arrow shifts the balance point forward and thus increases FOC. On my hunting arrows, I use 125-grain broadheads and add additional weight to the insert area to dramatically increase my FOC.
Today’s smallest-diameter carbon hunting arrows are very skinny compared to some of the popular aluminum arrows or large-diameter, thin-walled carbon shafts. A small-diameter carbon shaft has a surface area only half that of the larger diameter shafts. When you shoot small-diameter arrows in a crosswind, they exhibit less sideways drift than larger diameter arrows.
Because wind drift is directly related to the total surface area of the arrow, the surface area of the fletching must also be added to determine the total surface area of the arrow. As we’ve said before, it takes much less fletching to spin a small-diameter shaft than it does to spin a large-diameter shaft. So, you can use smaller fletching on small-diameter shafts, further decreasing the arrow’s total surface area.
You can also use much smaller fletching when using a mechanical broadhead than you can with a fixed-blade head. This is a big deal when you’re hunting out West, where it is often windy and shots tend to be longer. Another benefit of an arrow with minimal surface area is it maintains better down-range speed, which means more energy at the target and less down-range drop.
Wind drift is usually of more concern to Western hunters than whitetail hunters. However, I’ve spent many windy days in treestands while hunting in the Midwest. A small-diameter hunting arrow is more likely to save the shot if you forget to compensate for the wind. By switching from large-diameter arrows to small-diameter arrows with smaller fletching, you can cut your wind drift by more than half on longer shots.
In The Perfect Hunting Arrow – Part 3 we’ll complete our coverage of hunting arrows and hopefully you’ll be on your way to a better flying arrow and a successful hunting season.