1 - 19 of 19 Posts

#### Crusher

·
##### Registered
Joined
·
3,082 Posts
Discussion Starter · ·
I realize that some people pay no attention to their FOC. For those who do, what % of FOC do you shoot for 3D? I shoot 6%-7.5% generally, but question if this is too light. I have great groups, but wonder if I could get even better grouping. What is your experience?

#### SPECTRE

·
##### Registered
Joined
·
16,232 Posts
8% works well for me. Any lighter and my groups open up. Any heavier and I lose some speed.

I think the set up determines a lot when it comes to FOC. Especially shaft material. Aluminum tends to be a bit more forgiving on the FOC than carbon.

Just my humble opinion.

·
Joined
·
6,235 Posts
9% for me.

#### ursonvs

·
##### Registered
Joined
·
3,974 Posts
can someone tell me the equasion again for computing FOC? I used to have it with alot of other archery info and now i can't find it....thanks.

#### Shooter Mike

·
##### Registered
Joined
·
6,235 Posts
Found this in 2 seconds by searching google.com

: Here is the spreadsheet formula:
: ((((0.5*D2)+(2*C2)+(0.5*B2*F2)+((B2-1)*E2))/(D2+C2+F2+P2))-(0.5*B2))/B2
: Here is the spreadsheet data:
: B C D E F G
: 31.44 21.52 24.6 99 294.88 0.218626
: B = arrow length
: C = nock wt (includes supernock bushing wt)
: D = wt of vanes
: E = wt of nibb
: F = wt of shaft
: G = calculated F.O.C.
: Here is the formula in Larry Wise's book:
: -- --
: |.5xN + 2xF + .5xAxW + (A-1) x P|
: R = | ------------------------------ - (.5*A) | / A
: | N + F + W + P |
: -- --

: Variables:
: A = total arrow length including nock and point
: F = total weight of fletching
: N = weight of nock
: P = total point weight
: R = F.O.C. percent in decimal form
: W = shaft weight without nock, fletching or point
Here's a link to one of the many calculators on the internet that will figure your FOC for you: http://home.att.net/~sajackson/archery9.html

#### carpsh00ter

·
##### Registered
Joined
·
14 Posts
Here's a link to an online FOC calculator.

#### carbonman8

·
##### Registered
Joined
·
1,007 Posts
I have 10.2% FOC. I like 10% or more for 3D...

·
Joined
·
539 Posts
9% for me.

#### ursonvs

·
##### Registered
Joined
·
3,974 Posts
shooter mike

thanks for teh equasion...really appreciate it
Lee

#### ursonvs

·
##### Registered
Joined
·
3,974 Posts
ok i just figured my FOC and im not coming any wheres near ten %. im getting 50% straight up.

here are my arrows parameters:

ACC 3-18/560

shaft length only: 26 9/16"

length from front of tip to nock center:27.5

center of arrow: 13 3/4"

balance point: 12 1/4"

70 grain nibs

3 inch marco vanes = 18 grains total

gnock and insert

im getting like 44.3% FOC ...I know im doing something wrong

#### ursonvs

·
##### Registered
Joined
·
3,974 Posts
oh gawd im so lame....lololololol.
i was putting in the wrong measurement into the calculator.
refigured it and got 5.4%

think i need to go to 90 grain points and stop worrying about speed cause my groups arent worth a crap after 35 yards on bags.

·
Joined
·
1,554 Posts
11% for me

#### carbonman8

·
##### Registered
Joined
·
1,007 Posts
ursonvs, Do you have an insert in your arrow or are the nibbs glue in?

#### carbonman8

·
##### Registered
Joined
·
1,007 Posts
ursonsvs, You would go to a 7.4% with 90 grain points

#### georgestrings

·
##### Registered
Joined
·
852 Posts
Between 10% to 11% for me...

- georgestrings

#### justshoot

·
##### Registered
Joined
·
2,389 Posts
10 - 11 % for 3d depending on setup and arrow selection.

For longer distances I like a little less foc....less drop....

bowhunting, I like 12 % foc...

#### gvincent

·
##### Registered
Joined
·
151 Posts
Crusher,

Mine set up at almost 12%.
The only thing I notice is that there is more drop after 40 yards if you're short on yardage.
Grant

#### McArcher

·
##### Registered
Joined
·
437 Posts
FOC

I shoot the Gold Tip 22 series and I have mine set at 11 percent.
They just group better. Plus I think carbons like more FOC because of the stiffness in spine. A heavier point seems to make a big different in long range grouping.

Just my theory!

#### conquest

·
##### Registered
Joined
·
3,688 Posts
I like at least 9 %

1 - 19 of 19 Posts