Tuesday, February 26, 2013

Too Much FOC - Bow Hunting

Q: Hi Joe. I just switched to Victory’s VAP arrows, which use outsert-type adapters. I like the arrow’s slim design a lot, but I’m concerned about the arrow’s front-of-center (FOC) weight.

These arrows offer two types of outserts: aluminum (33 grains) or stainless-steel (92 grains). So far I really like the stainless steel version since it’s extremely durable, but they do increase the arrow’s FOC a lot when using a 100-grain point. I know adding FOC is a good thing for long-range accuracy, but will this setup take this factor too far? How much would you consider too much FOC?


C.P., via email

A: You can’t really put a number on ideal FOC weight. It’s best to shoot groups and decide for yourselves. As you point out, added FOC can be a very good thing because it creates better arrow control. Anytime there’s less weight at the rear of the arrow, then the fletching doesn’t have to do as much to properly steer the arrow on course. This adds up to enhanced flight stability, especially with fixed-blade broadheads.

This is why Olympic archers that shoot 90 meters prefer heavy FOCs—to optimize accuracy while using small fletching for reduced wind drift.

In addition, higher FOC weights go better with shorter arrows. This has to do with the distance between the center balance of the arrow (the point at which it balances on your finger or pencil) and the weight of the fletching. This measurement is reduced anytime the arrow is shortened, and for this reason, shorter arrows are theoretically less stable in flight, thus the need for more FOC. 

However, going beyond say 18 to 20 percent FOC will certainly come with a trajectory tradeoff. If you often shoot beyond 50 yards, then you’ll notice a drastic arrow drop at this distance compared to a normal FOC of 8 to 12 percent. 

To counter an extreme FOC weight with your arrows, you can consider a couple options: 1. You can switch to 85-grain heads.
2. And you can start using an arrow wrap at the rear of the shaft.

Both of these will lessen your FOC value.  –Joe Bell

Source: Bow & Arrow Hunting

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