FOC question

Schultzy · 02-06-2009, 04:59 AM

Years ago I never heard talk of FOC but It seems these days It's a common thing to hear on hunting forums. I've always figured I've done fairly well on setting my bow and arrows up to what they should be. I've recently got some Interest In this FOC so I checked mine and according to the formula I used I'm much lower then what I figured I'd be. My arrows have always flew good for the most part. I occasionly get one to kick sideways here and there but I'm sure that's more related to a bad release and possibly a short draw here and there. How do you guys check to see what your FOC Is? I've seen 2 different ways to do It. One way shows I'm good and the other shows I'm way low. If my FOC Is low I'd like to get It up to where It should be.

Thanks In advance.

Kanga · 02-06-2009, 05:14 AM

Steve,

What is your FOC according to both ways ??????????????

Schultzy · 02-06-2009, 05:20 AM

7.1% and 12% I think they were.

BobCo19-65 · 02-06-2009, 05:24 AM

Here is probably everything you need to know (and a lot more

):

Here

burniegoeasily · 02-06-2009, 05:51 AM

Its just the percent of weight forward. I simply find the fulcrum, measure it to the midline and find out the percent of mass that is forward. I like a higher foc for penetration. I use stiff shafts with lots of head weight. I do it for the quite shot and penetration. A higher foc can help the fletching stabilize the arrow a bit.

Low foc is ok with compounds, like 10-12%. But with a trad bow, I like to have much higher. Ive not calculated foc in a long time. Simply because ive had no problem with penetration. Ive stuck with a 650 grain arrow and 145 grain head. But since you mentioned it,I might have to figure mine, just to see what it is. Im like you, when it aint broke, I dont fix it.

Schultzy · 02-06-2009, 06:18 AM

Well I just checked It again using the formula Bob gave me In that link.

Here's the results using 2 different methods-

Including the tip- 7.7%
Not Including the tip- 12.1%

According to Ashby I should go by the 1st result. I've never had a penetration problem but I can say this that this summer I'll be experimenting with this and most likely I'll be adding brass Inserts to get my weight and FOC up. Currently right now my arrows weigh In at 561 grains. That Includes my 125 grain Snuffer.

Kanga · 02-06-2009, 06:25 AM

Steve.

I use a FOC of 24%.

Schultzy · 02-06-2009, 06:38 AM

Quote:

I use a FOC of 24%.

Wow!! What formula are you using? I Imagine your measuring the tip using that formula. I'll be throwing on some heavier Snuffers to this summer. I'll get It up there yet!!

Kanga · 02-06-2009, 07:44 AM

Steve.

Thats with a 125gr tip and 100gr brass insert

The next set of shafts I get are going to be the next spine up and use a 200gr tip and 100gr insert

That should give me some thumping power

stealthycat II · 02-06-2009, 08:05 AM

if you add 100 grains to your tip (in the formula you use) what would the % be then ?