Is my FOC o.k. ??
 

I was just checking out Jackson arrow tuning chart. What I want to know is that it say's my F.O.C. is 10.2% is this good ? If not what can I do to improve it ? I just re measured my arrow and didn't add that extra 1/4 "and it came up with the 10.2%

nubo

RE: Is my FOC o.k. ??
 

Personally nubo, I have found that measuring your FOC yourself will provide a much more accurate result then any calculator will. There are variables on nearly every setup that will throw things off when using a generic calculater. FWIW, I am currently shooting an FOC of 9% with aluminums (the calculator says 10.5), and innerloc braodheads. I usually go for a higher percentage, but my bow is tuned for the setup and I am shooting 1 1/2" groups at 25 yards, so I'm not messing around with it. Most people say that over 10% is good for broadheads with aluminum arrows and a little higher perentage for carbons.

RE: Is my FOC o.k. ??
 

Alot of people worry about the exact percentage..ast stated there is a generally agreed upon acceptable range of FOC of around 8-13% with 10% being about optimum.

But here's something you can go by that is much easier than figuring out all the formulae and whatnot.

Make sure you have at least 2.5 times as much weight on the point end of the arrow as you do on the back..include your point and insert weight, and compare it to the weight of your nock, unibushing if you use one, and your fletches.

You can get up to around 5 times as much point vs. nock end..but below 2.25 or so and you will likely run into FOC issues. The shorter the arrows, the less you can get away with, the longer your arrows, the more you'll want to get up to 3 to 5 times as much weight point vs. back.

RE: Is my FOC o.k. ??
 

That's easier then just measuring and finding the true FOC??? I'm not so sure.

RE: Is my FOC o.k. ??
 

It is if you know how much your components weigh...you can find it any manufacturers specs...

Nearly everyone has the weights for inserts, nocks and fletching listed. Much easier than getting an (and this is key) accurate FOC measurement by balancing the arrow, subtracting this, adding that, multiplying by Pi, etc :)

EDIT: For example..I have 111 grains on the front of my A/C/Cs... point and insert..I have 21 grains on the back...4" feathers , uni and nock... divide 111 by 21...and there ya go...

RE: Is my FOC o.k. ??
 

Jeff, so if we use your theory a 3" long Stoj's 125 grain head would give the same FOC reading as a 1" long Slick Trick 125 grain head. But is that an accurate FOC reading?

What if you placed the vanes at the very end of the arrow shank as opposed to placing them one inch from the end? Would your theory hold up?

RE: Is my FOC o.k. ??
 

It cannot account for specifics to that degree of course. However it is a good general indicator for those wondering if thier FOC is "good" or "bad"..taking into account generalities of where fletching is placed and length of tips.

While important, I believe FOC is overanalyzed more than it should be. The "guideline" I gave is more often than not a indicator of "is my FOC OK?, or is it not?" I think too many folks worry about their measured 10% FOC, and are being anal because they want it to be 11 or 12%. As long as it falls within an acceptable range, I don't feel the precision some folks go to is needed (other than to satisfy one's own need to be extremely precise).

Arrow conditions like consistent arrow spine, consistent weight, and consistent actual straightness need to be scrutinized more than FOC. IMO, of course:)

RE: Is my FOC o.k. ??
 

NO!

the only way to get an accurate foc reading is to balance the arrow.
I have posted the formula too numerous times it is getting redundant here it is one more time:eek:
http://forum.hunting.net/asppg/tm.asp?m=668748

RE: Is my FOC o.k. ??
 

Thank's bigpapa! I appreciate you posting to my thread ,I never seen your previous posting but I'll save it for future use.

nubo

RE: Is my FOC o.k. ??
 

FOC IMO is such an over rated measurement.

Get close - get somewhere in the 8 to 15% range and forget about it - it is a rare cause of hunting distance arrow flight or tune problems.

Its a reading that makes itself known at long ranges - even then its minute.