View Full Version : Foc?

11-16-2011, 04:14 PM
Ok I am not putting this on the AT because I don't want to be irritated by the superstars that know everything and think it's a dumb question. So knowing most folks here respond with respect and great knowledge can you direct me to a place to understand what this is and how I can check mine I am sure it is probablt wrong and just want to know what it's all about. Thanks all.

11-16-2011, 04:29 PM
i found some stuff for you to read.if it helps

11-16-2011, 04:37 PM
Hey thanks GD. I did a search on here and found lots and these are good starts as well. Understanding it now just was wondering how to figure it for my set up thought I might be a bit off of the 10-15 percent for hunting. Just need to figure it out now. Thanks again.

Hutch~n~Son Archery
11-16-2011, 04:43 PM
Hey Brad, its just like shooting darts the more weight you have in the front of the center of the arrow the better hitting power. On my old arrows I couldnt get all the arrows to hit the same all the time. I bought some new arrows and I hit great all the time. Checked the Foc and the old ones were too stiff and too little foc.


11-16-2011, 05:04 PM
Hey Hutch, just used some of the links given and with the current set up it says FOC is 10.36 with an arrow weight of 382.8 grains. Wouldn't think alot of KE with that. Punched in the 75/95 and it came out with 428.1 grains and a FOC of 11.97% with a 125 BH. Seems off some for hunting maybe?

Hutch~n~Son Archery
11-16-2011, 05:09 PM
Yeah that doesn't seem right. What is the length of the arrows you are shooting? What is the weight of the tips and the arrow.


11-16-2011, 05:14 PM
Hutch it's still the same in the sig with 100 gr BH

Hutch~n~Son Archery
11-16-2011, 05:20 PM
Hutch it's still the same in the sig with 100 gr BHHey Brad, gotta go I will run those through the one I use and see what I come up with. I will post as soon as I can. Mean while maybe someone else can run them.


11-16-2011, 05:46 PM
what the xxx is foc its so earritating not knowing what it is im getting stresses explain it in detail and with pics

Money Man
11-16-2011, 07:36 PM
Here's another link for FOC http://www.huntersfriend.com/carbon_arrows/hunting_arrows_selection_guide_chapter_4.htm#simul ator

11-17-2011, 01:49 AM
Thanks for the help guys. Used numerous calcs and they all come in at 10.3%. Hunters friend gave me the highest weight of my combo at 395gr. I even punched in the Easton 2315 and only change was the total arrow eight using 11.9 gr per. Guess it is what it is, lol.

11-17-2011, 05:28 AM
Uuh, 10.3? Can you get a little heavier insert for those GoldTip 5575's? Gold Tip makes a point weight system for about $8.00 a doz. Comes in 3 sizes; 10 gr, 20gr and 50grs, screws onto the back of your insert. That'll bring up your foc. So will switching from vanes to feathers.


11-18-2011, 06:21 AM
Thanks for the help guys. Used numerous calcs and they all come in at 10.3%. Hunters friend gave me the highest weight of my combo at 395gr. I even punched in the Easton 2315 and only change was the total arrow eight using 11.9 gr per. Guess it is what it is, lol.

Measure it yourself. .
Check out the last page of the Easton Arrow Tuning & Maintence Guide.....easy and and you'll know exactly what your specific arrow FOC really is. http://www.eastonarchery.com/pdf/tuning_guide.pdf
(the rest of the guide is pretty usefull as well)

Hutch~n~Son Archery
11-18-2011, 10:02 AM
I agree that you should manually check the foc it might not be as calculated


11-18-2011, 12:20 PM
my foc is 11.7 is that good or bad

Hutch~n~Son Archery
11-18-2011, 01:04 PM
FOC is important IMO 12% or above is what is recommended. When testing in my super shooter my pro arrows were too stiff and FOC was 10.50% the arrow were unpredictable. My new non pro arrows were less stiff and had more than enough FOC they hit in the same hole each time shot at 65yards.
This link explains it well http://archeryreport.com/2010/09/arrow-foc-basics-calculate/


11-18-2011, 02:19 PM
@ RLW and Hutch, I am planning on doing it manually as you suggested this weekend I hope. Will post the results after finished. Again thanks.

Hutch~n~Son Archery
11-18-2011, 02:44 PM
Good let us know!

Hutch :cool:

11-18-2011, 03:09 PM
why do they suggest a foc that is lower for 3d and target? Just curious.

11-18-2011, 03:10 PM
Hutch PM sent with measurements to verify for me. Thanks

Well I have measured and re-measured and it still comes out to anywhere from 10.1 t0 10.3 with 100gr bh installed. according to the GT charts the 5575 is geared for 85 to 100 gr heads and the 7595 are for the 125's so don't know if I can go t heavier heads with this arrow to change the FOC.

11-19-2011, 05:41 AM
Having gone almost full cirle now, we're back to the back of the arrow, have you tried feathers instead of vanes? Since you don't say in your signature just what vanes you're using, I'll use Bohning Blazers as an example; they weigh 6 grn each, so 18 grns, Gateway Rayzrs weigh 1.4 grn each or 4.2 grns, a difference of 13.8 grns, AND they'll provide more guidance. Just sayin. :)

11-20-2011, 06:49 AM
Was wondering about how to keep FOC up with other arrows that don't have the weight system like GT does. I have been looking into shooting Lumenoks and with their weight on the back-end it really pulls your FOC down. I have also been looking Harvest Time arrows and noticed their HT2 inserts are 14 grains, but their HT1 are stainless at 85 grains! That would easily solve the problem, but what if you weren't going that route? I don't want to go up to a 125gr head if possible. Just wondering what everyone thinks or knows.

11-20-2011, 07:20 AM
@ elkslayer4x5 I have blazer vanes. Haven't really thought about changing vanes though. Did manually check then and they still came out to 10.1 to 10.3 by calculations if I did it all properly. Am going to check using another suggestion with 125 gr tips to see what they show. Shot them this morning to see difference in flight and they did hit a little lower using the same pins but vertically they were almost exactly where the 100 gr are. I did notice at 10 degrees out the bow was even quieter with the 125s. Still trying to fix a tail left as well so getting frustrating in this cold. Might end up with tag soup this yr, lol.

Ok just checked using a 125 gr fp and the FOC is at 13.47 using 18 1/4 to ballance point and using 18 1/8 to ballance point comes out at 13.02. Used both numbers to cover slight differences when I measured. Question now is can I shoot 125 bhs on the 5575s without spine issues. Still trying to fix the left kick.

11-20-2011, 07:53 AM
As Bfisher reminds us, the bow is infinatly more adjustable than an arrow is, don't forget the limb bolts, a half turn may fix that flight problem.

11-20-2011, 08:02 AM
Thanks for the info ES but forgive the question but wouldn't that change the draw weight? And if I did make any adj to the limbs should I go half a turn up or down?

11-20-2011, 08:17 AM
Yes it will change the draw weight, but how much is a half turn?. Which way? the arrow will tell you. If your arrow spine is stiffer than required , more draw weight, lighter spine, less draw weight. :)

02-24-2012, 07:43 AM
Diggin this one up again. In a new spot with some new arrows. According to GT builder, with the new XT hunters I have coming for my X I'll be just shy of 9% (8.6-8.7) FOC depending on arrow length according to them. If I pick up their weights and put a 10g weight up front it will pull me up to 9.7 - is that 1% really going to make a difference? If I go with a 20g weight, I'll be closer to 11% at a finished weight of 392 which is more than I think I would like/need.

Am I over-thinking this?

02-24-2012, 07:49 AM
Ryan, check your PMs.