FOC ??????

wabi · Post by **wabi** » Fri Jun 16, 2006 6:59 pm

Decided to go back to aluminum shafts for hunting this fall, so I took some 2215's I had and cut them to 18" for my Phoenix. I crest dipped them for good adhesion for the fletching and started fletching this evening. I'm using 2" Blazer vanes and when the first one was done it came out weighing 380 grains with a 100 grain field point, and the FOC comes out to 9.5%. The weight is right where I wanted it, but the FOC concerns me. Should I increase point weight to get a higher FOC percentage?

Golden Eagle · Post by **Golden Eagle** » Fri Jun 16, 2006 7:35 pm

I only have 9.52 from my factory laser II's and they shoot great. I made up some 2117's last fall and they were light in the front, 7. something.

Big John · Post by **Big John** » Fri Jun 16, 2006 8:21 pm

wabi:

That's about what I'm getting as well, around 9.5% FOC on 2216's.
I don't like less than 12% and much prefer 15%. There is a difference in groupings at over 35 yds. with less FOC, especially in any wind. Or with Broadheads. However, under 30 yds. I cant tell any difference.

John

GaryL · Post by **GaryL** » Fri Jun 16, 2006 8:47 pm

I think so wabi, I thought you had a weight adjustment system made from threaded rod that you used for FOC

Thought I read about that from a post of yours and bstout

....

I do stand to be corrected on this ....

wabi · Post by **wabi** » Sat Jun 17, 2006 8:45 am

Gary L.
I usually add threaded rod to adjust, but I've also been thinking of switching to heavier points as my inventory of broadheads is going to have to be replentished before deer season anyway. I might use the threaded rod trick on a few to see if the increased FOC makes much of a differance. Keep forgetting that with aluminums it's easy to remove inserts!

wabi · Post by **wabi** » Sat Jun 17, 2006 10:27 am

Put a 125 grain point in one and the FOC changed to 12%. I think I'll do some shooting to test further, but the simplest thing would be for me simply to go to 125 grain points. Total weight of that arrow was 404 grains, and that should still be plenty fast enough for deer at my average range (less than 15 yards

).

Michael Stogre · Post by **Michael Stogre** » Sat Jun 17, 2006 12:50 pm

Re: FOC

Bill T. prefers to use a 100 grain wasp Boss broadhead for deer hunting.
Perhaps the emphasis on FOC is overdrawn. Bob Ragsdale in his
question and answer forum on the Bowhunting.net website says he
never pays any attention to FOC. This seems extreme to me. Perhaps
some of you experts could check with B.T. and B.R. to see what the
real truth about FOC is all about.

Matthias72 · Post by **Matthias72** » Mon Jun 19, 2006 5:37 am

Wabi,
a good system to change FOC without changing brodhead is installing into your shaft another shaft. For example 2215 inside diameter is 7.969mm; an aluminum shaft of 20 type (2020,2018 etc...) has outside diameter 7.937mm. To change FOC, put it with a little of glue (you have to decide how long and which shaft size), for example a 2020 2" long, into outside 2215 shaft, passing through the rear part (before you have to remove nock

). Use another 2020 shaft to push it deep until aluminum insert.

Matthias

GREYWOLF · Post by **GREYWOLF** » Mon Jun 19, 2006 10:31 am

This FOC questions has been around for a long time , After my experiance with GOLD TIP about the weight problem with there heavier brass inserts, I have been useing nothing but there lighter aluminum color inserts , But ! with one exception I bought 3 packages of there 20 grain inserts and 2 of there 10 grain threaded rod inserts.
This has given me the ability to make up bolts with any FOC I choose .
they can be screwed into the rear or front inserts, because they are the same thd. as your points, This last dozen I made for TJ out in CALIFORNIA weighed in at 392 grains an had a FOC of 13.
I think this might help you guys out with trying to get diff. FOC's just assemble the bolts screw in diff. combos , check your weight,check FOC , then epoxy the inserts in place Simple
GREYWOLF
[img][img]http://img.photobucket.com/albums/v651/ ... foc005.jpg[/img][/img]

GaryL · Post by **GaryL** » Mon Jun 19, 2006 3:33 pm

GREYWOLF wrote: This FOC questions has been around for a long time , After my experiance with GOLD TIP about the weight problem with there heavier brass inserts, I have been useing nothing but there lighter aluminum color inserts , But ! with one exception I bought 3 packages of there 20 grain inserts and 2 of there 10 grain threaded rod inserts.
This has given me the ability to make up bolts with any FOC I choose .
they can be screwed into the rear or front inserts, because they are the same thd. as your points, This last dozen I made for TJ out in CALIFORNIA weighed in at 392 grains an had a FOC of 13.
I think this might help you guys out with trying to get diff. FOC's just assemble the bolts screw in diff. combos , check your weight,check FOC , then epoxy the inserts in place Simple
GREYWOLF
[img][img]http://img.photobucket.com/albums/v651/ ... foc005.jpg[/img][/img]

Amen

Michael Stogre · Post by **Michael Stogre** » Tue Jun 20, 2006 12:46 pm

To add some grist to the mill here is a response of Bob ragsdale to
this question: "How many points will be instantly added to my score the
moment I achieve a perfect FOC percentage?

Dear Keith:

"Your question about why the FOC percentage can vary so much when
using the exact same weight broadhead when it is made in a longer
length to change the overall length part of the equation. I'd say it's
because whomever dreamed this up never thought about it ever
happening because if he had he would have made the equation based
on the shaft cut length and not included the point weight.

I did a compound crossbow manufacturing project and I assure you
that there is no way on earth it could possibly apply to their short
"arrows." A better question might be: "Why does FOC data not apply
to crossbows when they are arrows as well?"

In all these years I've never seen a top shooter every worry about
FOC. In my judgement when you make a shaft length or point weight
you are only changing the Arrow spine and if the change takes it to a
better match to your bow's needs it will group better regardless of the
FOC "reading."

For a further discussion of this topic by Bob Ragsdale enter his
search for window and read the one to Lucky and then Anon 4/11/2000.
(http://domino.htcomp.net/ragsdale)

GaryL · Post by **GaryL** » Tue Jun 20, 2006 4:21 pm

Well I kinda think this statement says it all "In all these years I've never seen a top shooter every worry about FOC. "

Another member of the forum here also states that he don't worry about FOC at all. He is also a top shooter ....