Arrow FOC

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Arrow FOC

Extreme front of center (EFOC) arrows aren’t a new concept. They’ve been talked about in traditional archery forums extensively for the past 10 years or so. But understanding what’s happening and why higher FOC influences and arrows flight and penetrating ability can be a little confusing to folks, especially those new to archery.

In this video I explain what FOC is, why it’s important, and how to measure it. Once you have two measurements, the formula to determine FOC is simple. You’ll need a total arrow length, from the throat of the nock to the base of the tip, as well as a measurement from the nock throat to the balance point. Plug that into the following equation and voila – %FOC!

((Balance Point/Arrow Length)- 0.5)x100=%FOC

All of this comes directly from Dr. Ed Ashby’s research into arrow lethality and penetration. There is a great discussion board dedicated to the topic at so be sure to check that out. You’ll find tons of great info on EFOC arrows there.

In future videos we’ll be building EFOC arrows in both carbon and natural material shafts so make sure you’re subscribed to the YouTube channel and signed up for the mailing list to get notified.

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By | 2018-02-07T06:13:23+00:00 February 7th, 2018|Traditional Archery|5 Comments

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  1. Shick February 7, 2018 at 7:26 am

    Great video; I am aware of FOC, but you really explained it well. Once again, great info.

  2. Jeff Tusing February 7, 2018 at 9:41 am

    Your comments on high and ultra high FOC are right on. I recently went to Africa for Cape Buffalo and for that trip I wanted all the penetration and accuracy I could get. The arrows I shot had a 22% FOC. I have a 32″ draw with my compound which works against high FOC. With shorter draw lengths higher FOC is easier to obtain. I found this set up to be more accurate than my previous hunting arrows, they were around 8%. I have yet to change to a higher FOC arrow for my recurve and long bow because of the lack of availability of heaver points for wooden shafts. If you know where I can get heaver tips please let me know.

  3. David February 7, 2018 at 2:52 pm

    Great vid clay!

  4. Clay February 8, 2018 at 6:36 am

    Hi Jeff, there are lots of options for heavy glue on heads. Tuffhead and Abowyer are both making 300gr heads. I think Grizzly also makes a heavy head. I’ve used both the tuffheads and grizzlies and both are good options.

  5. Ross McCollum February 25, 2018 at 2:42 pm


    I recently listened to Dr, Ashby videos and have read all of his papers. I am now, since Dr. Ashby’s studies are based on his results of shooting into animals, a believer in high FOC. According to Dr. Ashby numbers, a 650 grain carbon arrow for my 49# hybrid longbow should be a reasonable combination. I am looking forward to your upcoming video on building high FOC arrows.

    Good Hunting,

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