High FOC and weak carbons

[xtrema312]

Has anyone found that with high FOC like over 20% a bare shaft tends to go to the fletched shaft group or close to it even if it is too weak?

It seams to me like once I get around 20% and over it doesn't matter a lot what the spine is because the point kind of drags that arrow there more than the back of the arrow or shaft flex driving the point off line.  Is it just me?

[Rob DiStefano]

can't answer about comparing bare shafts to feathered shafts.  i just don't see a need to do that kinda testing.

my 55# mohawk uses 29.5" beman 500's, 665 grains total arrow weight, 31% efoc.  the feathers are 4" nanners, 75x105 four fletch with only a tad of offset.  

i test the arras out at 5 yards to 35 yards.  they fly clean and hit what i aim at if my form/release is good.

yep - i do find that high foc works in my favor ... big time.

[xtrema312]

Rob what do you have out front of that shaft?  about 400 gr. or so?

[Richie Nell]

xtrema312,
I agree with Rob....I don't see the reason for comparing to fletched arrows.  Being RH, if it kicks left it is weak, right it is stiff.

Yes, high EFOC does tend to steer the arrow better creating easier tuning.  Like I have mentioned before and confirmed this with Dr. Ashby...others may agree...My 30% UFOC 900 grain arrows seem to fly with the same trajectory as a 750ish gr. arrow with 15-20% FOC.  I think the reason is exactly what you are seeing...heavy weight forward steering the shaft behind it.

[Jason R. Wesbrock]

What distance are you shooting for your bare shaft tuning? You may need to shoot from a little further away. It takes some distance for the shaft to kick out, pick up wind resistance, and plane. The closer you get to proper tune, the further you will need to shoot to induce planing.

[xtrema312]

25 yd. most of the time.  I don't shoot much farther with bare shafts because I only shoot for fun past that.

[Rob DiStefano]

Originally posted by xtrema312:
Rob what do you have out front of that shaft?  about 400 gr. or so?

125gr woodsman (or judo or field point), 125gr steel adapter, 100gr brass insert, 155gr internal footing behind the insert.  all that stuck on a wimpy 500 shaft - but hey, it works great for me!  :D

[dick sable]

Rob,
WOW that really is EFOC. By the way, at what point is foc considered efoc, generally speaking?  Also, how does the internal footing work "behind the insert"? Interesting stuff. Thanks.

[SS Snuffer]

Beeman MFX 500 100gr. brass insert and 125gr point 29 1/5 in arrow and 28 in. draw. Bare shafts real well for me. 18% FOC

[ishoot4thrills]

Check out my signature and see my setup. It would seem to be too weak spined, but it works great with great arrow flight.

[8leg-lover]

Easton Axis 500 29" two standard hit inserts with 200 grain point/broadhead, 3X4" feathers, 23% FOC works awesome for me out of three totally different bows.

Carl

[Rob DiStefano]

Originally posted by dick sable:
Rob,
WOW that really is EFOC.

indeedy it is, sir - and that's my low efoc setup, too!

By the way, at what point is foc considered efoc, generally speaking?  

i dunno if there are any rules for efoc, but i look at it thisaway - high foc is in the 18%-24% range, anything 25% and over i'll call efoc

Also, how does the internal footing work "behind the insert"?

the footing i use is documented on the 'how to' forum, and it's basically a 4.5" length of plastic spine insert that's loaded with a 16d nail and rammed down the carbon shaft from the nock end 'til it seats tightly behind the point insert.

 http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=2;t=000103



Interesting stuff. Thanks.

........

[Richie Nell]

According to Dr. Ed's research, he defines EFOC as 19%-30%.  Over 30% is Ultra-EFOC.

He also states that the point at which an  increase in penetration is noticed is 19%.  And it continues to be significant with each FOC percent after that.  The higher the better.

[xtrema312]

Good info.  I know my weak shaft high FOC arrows fly great out a ways and to the target.  They don't tear nice holes in paper at close range.  I don't have  BH's in the point weight I am shooting so I don't know how they would fly.