4 Steps To Perfect Broadhead Flight
Going From Field Tips To Broadheads Requires Arrow Tuning On A Higher Plane

Thousands of bowhunters will suffer hours of frustration, and that’s before they get hunting. I’m talking about the unfortunate hunters who will have trouble making their broadheads fly true.
They’ll fool with their setup for days only to find they still can’t get their broadheads to group or hit where their field points do. Sadly, there’s little reason for this struggle. Yes, broadheads are more difficult to shoot accurately than field points, but making broadheads shoot well doesn’t require a Ph.D. or years of experience as a bowsmith. It only requires that you pay attention to certain details.

“What details?” you ask. That’s what this article is about. Much can be learned about bow tuning for broadheads by observing the arrow’s front-of-center balance point, making the right fletch choices and knowing how to check broadhead alignment. Follow the four steps listed here, and the odds are your broadheads will group better than ever.

The Well-Tuned Bow
The first thing you have to do is make sure your setup is truly tuned. Don’t be fooled into thinking that your bow is in tune because you can shoot tight groups with field points. Field points can be very forgiving, and it’s possible for an out-of-tune bow to shoot one-inch groups at 20 yards with field points. (This is why mechanical broadheads tend to group better. They’re much more like field points.)

Most broadheads, however, aren’t going to let you get away with bad tuning, especially if you have a fast bow. This is because the blades on a broadhead can act like wings and steer an arrow all over a target face. Launch an arrow poorly and the blades will catch air and drift off target right from the start.

Easton Technical Products has a great technical bulletin on tuning that’s very easy to follow.

Make sure to re-check your arrow spine before you begin tuning.Having an arrow that’s too stiff or soft will make it impossible to achieve perfect broadhead flight. Make sure to consider all the variables that influence spine stiffness. According to Easton, the variables are:

1. shaft size (diameter and wall thickness 2. shaft length (+/- 3⁄4 to one-inch can significantly change shaft stiffness) 3. weight of the broadhead to be shot (+/- 25 grains can significantly change shaft stiffness) 4. draw weight of the bow (+/- 2.5 to five pounds can significantly change shaft stiffness) 5. archer’s draw length (certain shafts become significantly weaker when cut past 28 inches) 6. string material (Dacron strings are slower and require a slightly softer arrow) 7. type of bow (recurve or compound with a wheel, soft-cam or speed-cam) 8. finger or mechanical release 9. (finger shooters require a slightly stiffer arrow) bow length (bows less than 40 inches in length require a slightly stiffer shaft) 10. overdraw length, if used (three-inch-plus overdraws require a slightly stiffer arrow)

If you shoot Easton shafts and have a computer, download the free Easton shaft selector to select the right shaft. The program is much easier to use than a chart. Easton’s website, www.eastonarchery.com, If you have to use a chart, or shoot another make of arrow, be certain to read the instructions on shaft selection very carefully. Finally, keep in mind that your setup may vary enough to require a different size shaft than the one recommended.
Now that you’ve got the right arrow, you need to tune the bow to the shaft. Note “You need to tune the bow.” You don’t have to be the brains behind the tuning, but you can’t have your local archery shop do this for you.

The Pro shop can’t paper-tune or bare-shaft-test your bow for you. You have to do the paper/bare-shaft/group testing, other people are likely to shoot your bow differently than you do. A true tune can only be achieved if you’re the one doing the shooting. If you don’t feel confident about the mechanics of tuning, have the shop pro adjust the bow while you shoot arrows.

You don’t have to tune with broadheads at this point; field points are fine at this stage. Later, you’ll want to shoot at long range with broadheads (anywhere from 30–45 mtrs depending upon your skill level) to test your tune. If you’ve completed the other steps in this article and are still having trouble getting your broadheads to group, then you probably still have a tuning problem. The same is also true if your field points and broadheads have a different point of impact.

The Right Fletch
A lot of bowhunters go for extra speed by reducing arrow weight. That’s OK, within reason, but don’t save weight by cutting back on the size of your fletch. Arrows with field points can get by with very little fletch guidance. The same is not true in regard to broadheads. You need a lot of fletch to counteract any attempt by the broadhead to steer your arrow from the front of the shaft.

What is FOC?
If there’s one variable of broadhead flight that’s often overlooked, it’s the arrow’s front-of-center balance point, or FOC. In practical terms, FOC determines how much leverage the fletching has to correct the arrow’s flight. The farther forward the balance point is from the center of the arrow—the FOC point—the longer the lever the fletching has to work with and the easier its job. The general recommendation for FOC is 12 to 15 percent for broadhead-tipped arrows. This compares to a recommendation of 8 to 11 percent for field points (for pure target applications). The difference in suggested FOC is due, in part, to the longer length of a broadhead. It’s also due, in part, to field points not having the ability to steer an arrow like a broadhead can.

Finger shooters, and those shooting shafts less than 26 inches in length, should probably look for a higher FOC. This is because shorter arrows are inherently less stable, and finger shooters, once again, need a little extra help to correct the normal arrow wobble upon release.

Note that it’s possible to shoot very accurate groups with field points with less than eight percent FOC, but again, field points are more forgiving than broadheads. Just as with fletch size, it’s better to err on the large side with FOC. You don’t want to go overboard, though (past 18 percent). Too much FOC makes your arrows point-heavy and less aerodynamic downrange.

How to figure out your arrow’s FOC? The Easton computer program has a calculator that will do the job for you. If you don’t have the program, you have to do the maths yourself. The formula is: 100x(A-L/2)/L

A is the distance to the arrow’s balance point from the nock of the arrow, and L is the total arrow length. All you need is a tape measure and something to balance an arrow on to use the formula. First, balance the arrow and mark the balance point. Then measure from the throat of the nock (where the string fits inside the nock) to the mark you made at the balance point. This is the arrow’s balance point (A).

Next, measure the length of your arrow from the throat of the nock to where the insert goes into the shaft. This is the arrow length (L). (If you use carbon shafts with outserts, measure to where the point screws in.) Finally, input the figures into the FOC formula. For example: If you had a 30-inch arrow that balanced at 19.5 inches, the formula would be: 100x(19.5-30/2)/30=15% FOC.

What do you do if your arrow’s FOC is too low? You might have to use a heavier broadhead or change shafts. Adding a heavier head can change arrow spine, meaning you might have to use a different arrow or, at the very least, re-tune the bow.
Changing to lighter nocks,vanes or feathers will also bring your FOC forward.

The Final Step
Make sure your arrows are perfectly straight and that your broadheads are perfectly aligned.
Some broadheads fly differently than others if the bow’s tune is off, the FOC is wrong or the fletch is too small, but you should be able to get almost any head to fly tolerably well if you take all the variables into account.

Troubleshooting
If you’re still having trouble, go back over these four steps again. In particular, recheck your tune and consider adding a little extra fletching. Be aware that a modification in one step can influence other steps. For example, switching to a heavier head to improve FOC can make a shaft too soft and change your tune. Note that all of the above steps apply to shooting mechanical heads too. While they’re generally easier to tune than fixed-blade heads, they’re still not field points.