As with any sport or endeavor involving mechanical devices, bowhunting has many technical aspects that can cause veteran shooters and beginners alike to get lost in the weeds.

It wasn’t always this way, of course. When bowhunters were roaming the hills with simple stick-and-string recurves and longbows, and shooting home-assembled cedar shafts, life was necessarily simpler. You learned the limits of your equipment, refined your shooting skills to match, and that was that.

While archery can still be relatively simple in execution, technology offers those with a desire to maximize its benefits the opportunity to take potential performance gains to the max. For example, we all understand the importance of matching arrow deflection (spine rating) to the bow’s draw weight and length in order to achieve good flight efficiency and accuracy. What’s not so well understood by many bowhunters xe2x80x94 especially those new to the sport xe2x80x94 is the importance of arrow weight distribution.

When we talk of a hunting arrow’s weight distribution, we’re really discussing a weight bias toward the front half of the shaft called Front of Center or, in common bowhunter-speak, F.O.C.

To quickly grasp the concept of F.O.C., consider a stick about four feet long. One end is thick (let’s say two inches in diameter) and it tapers down to a sharp point. Now grasp the stick from the thick end and try to chuck it like a spear, tapered point first. You’ll find that the front of the stick will not track well in a straight line. It will want to wobble and upend, with a good chance that it will flip completely over.

Now throw the stick by holding it from the tapered end, heavy end first. Big difference, right? All that forward weight keeps the stick tracking relatively straight, with the lighter back end following dutifully behind. Add some fletching on the back and you’ll see even straighter flight.

This same principle applies to bowhunting arrows, although the results aren’t as exaggerated as in our stick example. The point is, arrows that have more weight skewed toward the front half of the shaft (balance point within the front half of the shaft) will fly straighter than arrows that are equally balanced at the front and rear (balance point at the center of the shaft) and exceptionally better than arrows with weight skewed to the back half of the shaft.

This concept has been understood probably since the earliest days of the bow and arrow, but its importance was somewhat forgotten in the modern age. That, of course, has changed considerably in recent years. With today’s advanced, high-speed bows being hyper-critical of almost every aspect of arrow construction, ensuring proper arrow weight distribution has never been more important for achieving both short- and long-range accuracy. For bowhunting applications, a proper weight-forward bias is also important for good arrow penetration.

If you’re new to the F.O.C. discussion, you’re probably thinking, “All that theory talk is well and good, but what does it mean in the real world?”

Let’s take a closer look.

As with most things related to physics, there is never a free lunch xe2x80x94 gain something here, lose something there. With arrow F.O.C. balance, the gain of straighter flight is offset by a drop in trajectory xe2x80x94 the arc of the arrow between the bow and the target. As the percentage of total arrow weight shifts from the center of the shaft toward the front of the shaft, arrow drop tends to increase. As the shot distance increases, arrow velocity drops and wind drag on the fletching combines with the nose-heavy weight distribution to drop the trajectory more quickly than an arrow with its weight balance nearer the center of the shaft.

“More quickly” is relative, though. We’re talking small degrees of drop that is dependent on arrow velocity. An arrow shot from a lighter weight bow with a shorter power stroke is going to have a greater drop in trajectory than the same arrow shot from a heavier bow with a longer power stroke.

If you’re starting to think “Hey, this F.O.C. causes arrows to drop faster, so why would I want it?”, understand that there are offsetting benefits to the bowhunter for having a weight-forward distribution, primarily improved accuracy and penetration. Drop can be easily compensated for by adjusting your sight pins. That’s not a problem. The trick is finding the right balance for your setup and your hunting style or needs.

But before we go there, we need to determine the optimal F.O.C. weight distribution. Fortunately, this is a well-established parameter. For this, we need look no farther than the arrow experts at Easton. Their years of testing and practical in-the-field shooting have given us what is generally considered the ideal F.O.C. percentage for a bowhunting arrow xe2x80x94 one that delivers good flight characteristics, accuracy, and penetration with acceptable trajectory performance. That parameter, or F.O.C., is 10xe2x80x9315%. What this means is that the ideal arrow balance for bowhunting places 10 to 15% more of the arrow weight in the front half of the shaft than in the back.

How do you figure F.O.C.? It’s a simple formula, and Easton provides the steps for F.O.C. calculation here.

Once you have calculated your arrow’s F.O.C. percentage, it’s a simple matter of adjusting to increase or decrease the F.O.C. as needed. For example, bumping your broadhead weight from, say, 100 grains to 125 grains, will increase your F.O.C.

Another common method that really moves the needle is installing heavier inserts, such as those made of brass. Moving to a heavier broadhead and using heavier inserts is usually enough to put the F.O.C. of most arrows into the sweet zone. If not, modifications to the back of the shaft are possible, such as using feather fletching instead of plastic vanes.

Although establishing a practical F.O.C. is straightforward, getting there can be a bit frustrating when you try to round up components to get the job done right or you must modify existing arrows. Unfortunately, this is where a lot of bowhunters give up, especially if they don’t have the equipment or supplies to install inserts or re-fletch arrows.

The good news is, there are ready-made solutions xe2x80x94 particularly for bowhunters who desire the higher velocity and flatter trajectory of lighter-weight arrows (versus the greater impact energy of heavy arrows) for shooting longer distances, or for those with shorter draw lengths or lighter pull weights who need top speed. Easton, for example, offers two arrow shaft systems that establish ideal F.O.C. right out of the box.

The 6mm Hexx Enhanced F.O.C. is a lightweight, high-velocity carbon shaft developed for the bowhunter who requires maximum possible speed and optimal precision for longer-distance shooting, such as in open country when pursuing mule deer, antelope, or whitetail. The Hexx is built with a straightness tolerance of +/- .001 inches, which translates to point-of-impact consistency out to those extreme distances.

To achieve a custom F.O.C. percentage, the 6mm Hexx Enhanced F.O.C. comes with 8-32 Brass H Break-Off inserts. At full length, these inserts add 75 grains to the arrow. If that is too much for your desired F.O.C., you can break off the rear portion of the brass insert and remove 25 grains. Available in 400, 330 and 260 spines, the 6mm Hexx Enhanced F.O.C. has a moderate shaft weight of 7.2, 7.9, and 9.3 grains-per-inch, respectively.

For bowhunters who do not anticipate long-range shooting (40 or 50 yards plus) yet need that delicate balance of good speed and downrange kinetic energy for no-doubts penetration, the 6mm Bloodline Enhanced F.O.C. shaft is a solid choice. Like the 6mm Hexx, the Bloodline includes the Brass H Break-Off inserts so you can custom-tune the arrow’s F.O.C. with your preferred weight broadhead.

The 6mm Bloodline is a great choice for archers who are shooting moderate- to lower-weight bows because these shafts have a slightly higher GPI weight (7.7, 8.7 and 9.4 GPI for the 400, 330 and 240 size shafts, respectively). This provides that extra bit of terminal kinetic energy needed to ensure good penetration from shorter draw length/lighter draw weight bows.

Regardless of the equipment you shoot and the path you take to get there, establishing a good F.O.C. percentage in your hunting shafts is important for accuracy and penetration because the more stable the arrow in flight, the more precise your shot placement will be and the more energy that is retained and focused on the impact point.

Yes, it can take time and effort to setup your arrows just right, or you can take the ready-made solution with arrows like the 6mm Hexx and 6mm Bloodline. Whichever way you choose to go, know that it will be time well spent when it’s time to notch your game tag.

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