As we discussed in our previous article, “Guide to Purchasing Crossbow Arrows,” there is one subject that I feel needs to be expanded upon. The Front of Center (F.O.C.) is a term that has become a recent buzz word in both the archery and bow hunting communities. The reason that it is an important term is because your arrows F.O.C. is going to affect how the arrow is going to fly. Having a front of center that is specifically matched to your setup will allow your arrows to have the perfect balance point, and in turn will make them fly better. It should be noted, that because crossbow arrows are shorter than archery arrows, F.O.C. will not contribute too much to arrow flight. For archery arrows, this is a different story. The obvious question that is probably on everybody’s mind is, “which FOC is the best for me?”
There are various thoughts on what F.O.C. is best, but something that is certain is that the “best numbers” are going to be different for competitive archers (paper shooters) and bow hunters. The reasoning for this is because F.O.C. matters more and more, the further you are from your intended target. An ethical (and effective) hunting range is usually in the 20-30 yard range. Competitive archers have a tendency to shoot at targets that are much further away. The further that you are from your target, the more extraneous circumstances can have a negative effect on flight. It is for this reason that stability is key.
A good way to visualize this concept is by thinking of a shuttlecock. When you hit it with a racquet, the heavier part of the object moves to the front in order for it to guide the shuttlecock along. The same can be said for arrows. If you do not have enough weight on the front of the arrow, then the back of the arrow will at some point try to pass the front of the arrow. This will usually cause erratic flight patterns. Having the correct weight on the front of your arrow will aid in stabilizing it.
Most of what I have seen during recent times is that an F.O.C. in the 10-15% range is what most bow hunters tend to find is the most effective. As I say this, I know that there are people who shoot arrows that have a front of center that is under 10% and there are hunters who feel more comfortable in the 15-18% range. I feel that the reason for this is that these hunters may be shooting at different animals and may possibly be shooting under different weather conditions.
Some of the common F.O.C. percentages for shooting styles are as follows:
· International Archery Federation: 11-16%
· Bow Hunting 10-15%
· 3-D: 6-12%
Personally, I do not feel that front of center has as crucial of an effect when you are hunting, as it does when you are shooting in long-range outdoor competitions. Competition arrows that have proper F.O.C. (and sufficient spine to do so) will undoubtedly perform better in the wind. The reasoning for this is that speed is not a necessity when you are target shooting. The focus is on accuracy. As with almost any part of this sport, you will need to test out some different F.O.C.’s and see what fits the best for you.
How is it Calculated
The first thing that you want to do, is make sure that you measure the length of the arrow from the groove on the nock, to the tip of the point that you will be using. Next, find a pyramid shaped object with a sharp edge. This is where you will be balancing your arrow. Move your arrow along the edge until it balances. Now measure from the nock to the point where it balances. Once you have done this, you take the total length of the arrow and divide it in half. This will give you the true center. Subtract the measurement of the true center, from the measurement that you took from the balance point to the nock and you will get a number. Divide that by total length and multiply by 100 for your FOC %.
It sounds confusing, but here is the example written out with numbers:
Length of entire arrow: 30”
Nock to Balance Point: 18”
(Balance Point-True Center)=18”-15”=3”
(Balance Point-True Center)/Total Length=3/30=.10
.10 x 100= 10% FOC