EFOC ?

[anw0625]

I know that this has been talked about but can't seem to find it.  When you are setting up your arrows what EFOC % do you aim for?  Thanks!

[kibok&ko]

20 to 25 !

[Friend]

A stiff but light arrow front loaded such that the spine is ~30#'s less than the spine required by the bow.

[dave19113]

As heavy as I can just so as not to compromise accuracy. although I have found that by going a little on the heavy side increases my accuracy.

[monterey]

Mine shoot better with more FOC too.  Presently I'm shooting a 23/64th cedar with 190 broadhead that go 19.35%.  Am exploring ways to get it to 25%

[Davie C.]

Lots of FOC is a great way to toughen up arrows for stumping too. It lets you use a stiffer shaft (usually thicker sidewall/tougher), and most of the energy gets dumped at the point end on impact so the shaft takes less of a hit when shooting into hard targets by accident. Its a win-win!

[Tutanka]

I am currently working with some full length CE 75 Heritages that have 300 grains up front and three 5" long feathers.  The total arrow weight for this set up is 595 grains and the EFOC is 25%.  I have never shot a arrow with this much weight up front, but thought it would be fun to try out.  I will be interested to see the affect it has on the arrow when shooting past 30 yards.  My bow is a r/d longbow cut to center that is 53 lbs. at 28 inches, my draw length is 29 inches.

[Mint]

tutanka, how do you get those arrows to fly? I just put your info into Stu Millers Dynamic Spine calculator and it is saying your arrows would have a dynamic spine of around 25lbs while your bow is in the 60's. You need to use CE 350's with that much weight up front and full length.

[Friend]

Tutanka...

The greater you go up in FOC such as ~25% and up, the progressively lower the required arrow dynamic spine.

Approx. 30# less spine, in some case or more, may be required for 30% and above FOC arrows.
A viable set-up for you to test that may tune nicely would be the following:

Victory VForce HV400 (6.2 gpi)
~ 30 ¼'
400 gns up front
3 x 4" feathers
~604 gns tot. wt.
31.8% Ultra-EFOC

Actually hunted with 350HV's w/400 up front this spring and the bare shafts and Big 3 (300 gn) BH's tuned great. My shelf was cut 1/8" past center requiring ~10#'s more of spine. Was able to shoot the set-up effectively out to 25 yards. The biggest issue incurred was that I could not afford the targets. Went thru an 18 in 1 Rhinehart in 3 1/2 weeks and a Dick's Eagle layered field pt target in 2 1/2 weeks. Both targets were ~$90 each. This set-up was also shooting to the ply wood which backed the indoor targets at the indoor wheelie range.

[Tutanka]

Originally posted by Mint:
tutanka, how do you get those arrows to fly? I just put your info into Stu Millers Dynamic Spine calculator and it is saying your arrows would have a dynamic spine of around 25lbs while your bow is in the 60's. You need to use CE 350's with that much weight up front and full length.

For me personally I find the spine calculator to be next to worthless, maybe I just haven't used it enough.  I use the Adcock tuning method and then build out my strike plate. Whenever I do use the calculator it always give me a higher spine than I really need.  The highest spine CE that I have shot is a 150, even though for most of my setups the calculator shows that I need to shoot 250's or 350's.  I am lucky enough to live close to Rocky Mountain Specialty Gear and am able to tune a lot of different spines that they have in their shop without having to spend the money buying them.

[reddogge]

I don't aim for anything. I set the arrow up to shoot out of the bow straight and then measure it.

[anw0625]

Thanks guys for your help.  Right now I am getting around 20% and was wondering if that was good enough.

[Rob DiStefano]

don't intentionally set up for efoc or uefoc or even foc.  that's putting the horse before the cart.  

instead, use arrows that are at least 9gpp, get them to consistently fly extremely well, keep yer broadheads super sharp.  the rest is window dressing, of sorts.

[Friend]

anw0625...

If your arrows are tuned well then you are good.
(Assuming you have adequate arrow mass)

Do note that the enhanced penetration benefits of FOC are not even measureable until you reach and start to exceed 19%.

[Mint]

Stu's calculator has worked great for me but the most important input is the shelf location. If that is off then everything will be way off. But people have different shooting forms too, I shoot a longbow that is 1/8" from center and draw 53lbs and 28" CE 150's fly perfect with 200grs up front.