Traditional Archery Discussions on the Leatherwall


High FOC question

Messages posted to thread:
Fletch36 10-Jan-19
Longcruise 10-Jan-19
Buglmin 10-Jan-19
Draven 10-Jan-19
Beendare 10-Jan-19
Fletch36 10-Jan-19
Fletch36 10-Jan-19
Draven 10-Jan-19
Beendare 10-Jan-19
Fletch36 10-Jan-19
Fletch36 10-Jan-19
Jim 10-Jan-19
Twan 10-Jan-19
Fletch36 10-Jan-19
Draven 10-Jan-19
Draven 10-Jan-19
George D. Stout 10-Jan-19
JRW 10-Jan-19
fdp 10-Jan-19
gluetrap 11-Jan-19
George D. Stout 11-Jan-19
Orion 11-Jan-19
2 bears 11-Jan-19
camodave 11-Jan-19
JRW 11-Jan-19
fdp 11-Jan-19
Glynn 11-Jan-19
Orion 11-Jan-19
gluetrap 12-Jan-19
LongTrad 12-Jan-19
Rick Barbee 12-Jan-19
Longcruise 13-Jan-19
tradmt 13-Jan-19
Mike Walker 13-Jan-19
B.T. 13-Jan-19
Fletch36 13-Jan-19
Fletch36 13-Jan-19
B.T. 13-Jan-19
Mike Walker 14-Jan-19
Mike Walker 14-Jan-19
PistolPete 14-Jan-19
From: Fletch36
Date: 10-Jan-19




Hi all, for those of you familiar with this, what percentage do you shoot? I have some arrows coming that work out to be around 17% FOC -- is that too much? I'll be shooting 29" 240 shafts with 100 gr. inserts our of a 63 lb. Super Diablo. I can play around with point weight. I think that arrow is between 9 and 10 gpp. I've been shooting carbon arrows in the 6-7 gpp range. What do you think?

From: Longcruise
Date: 10-Jan-19




Well, "too much" in what context? I think it would be a fine hunting arrow.

From: Buglmin
Date: 10-Jan-19




A 240 with 100 grain insets, and what weight tip got you to 17% foc? That's a very stiff shaft.

I used an arrow last fall with 20% foc, arrows flew good, but I wasn't happy with the penetration I got on a deer. I wasn't happy with them and changed arrow setups the minute I got back to Colorado. I ended up with an arrow with 16% foc and had great penetration, breaking the pelvic bone on my Colorado mule deer and sticking ten inches out of his left ham. He made it thirty yards. Guys will argue about 30% ehfoc being better, but you ever shoot a ehfoc arrow in the wind?

From: Draven
Date: 10-Jan-19




I really don't do the math by myself, I use Stu's calculator and once all the data is on, my carbon arrows I usually use falls in 9gpp with 20% FOC area -(31.5 POB, 350s with 200gr point).

For my wooden arrows I shoot from longbows, they fly great with 14-15% FOC and the arrows are in 7-8gpp area.

PS For my Super Diablo #70@28" the arrow I use is ~7gpp and ~17% FOC (total arrow 500gr with 180gr up front)

From: Beendare
Date: 10-Jan-19




Its all about perfect arrow flight.

IMO.....FOC is the LEAST important factor in the archery world. So striving for a very high FOC and sacrificing the other important factors is a bad idea.

From: Fletch36
Date: 10-Jan-19




I didn't aim for high FOC, I just wanted a carbon arrow that was heavier than I normally shoot out of my other bows since this is a 60 lb. bow. This give me a GPP of 9.5 which would be quieter and easier on the bow than a 6-7 gpp arrow which is what I normally shoot. They shoot nice and flat, but not necessarily super quiet. I get great arrow flight, but most of what I've read here lately seems to favor a slightly heavier arrow. Maybe I just need to choose another arrow material.

From: Fletch36
Date: 10-Jan-19




I'm using the 3-rivers calculator.

From: Draven
Date: 10-Jan-19




Personally, I have a hard time to get 600gr arrows with carbons that will fly great from my SD without spending +$20 / arrow. With aluminum is different.

From: Beendare
Date: 10-Jan-19




Ok, Gotcha Fletch. I typically shoot 10GPP to 12 GPP for my hunting arrows.

I've had good luck with that range...though a very efficient BH will make any arrow very effective.

FWIW, I think striving for a quiet hunting setup is key. Some of these species like Axis deer, Javelinas, coyotes, etc are string jumping machines...and considering we need to be close...it really makes a quiet bow/arrow an important factor, IME.

[I just had 5 shots at Javi's....emptied my quiver actually....and all jumped the string- All shots looked great-frustrating. It was dead quiet, on wide open ground between 20-27 yds...those suckers were jumpy. I gut shot one, he moved on the shot but not enough to miss- recovery after a long followup

Where FOC comes into play is; I've played with some of the very high-30%- FOC setups and they were not as forgiving of any tiny form flaw.Not what you want in a hunting situation....I want a forgiving balanced setup.

IME, arrows in that 12%-20% plus/minus FOC range have given me the best all around performance...though its all about arrow flight and how well they group in different situations....I don't worry so much about the actual FOC %.

Note on Javi's; Those thing are made for bowhunting as they don't seem to see too well. They will spot movement...so super slow stalking is key. It is a bit of a gut check when getting in close to a bunch of them and there isn't a tree for 1/2 mile. They could easily turn you into dog food real quick if they wanted to.

They aren't very big, but even the 30# era will have very sharp tusks...and they are mean and very defensive little buggers. They are very callable with a varmint call....but be careful what you wish for if not packing a backup weapon.

From: Fletch36
Date: 10-Jan-19




Thank for all the responses! I also have 30" 2117s that will probably do the trick as well. Like you all say, I'll just see how the arrows that I have shoot through it and go from there. The bow isn't in my possession yet, and it's traveling via Parcel Select, so it'll probably take a couple weeks to arrive from Cali. Javelinas would probably be a lot of fun -- living in PA, I haven't seen any running around lately. If I ever get a chance to hunt in the south, I'd love to give them a try. I saw Steve shot a couple on Meat Eater and they looked like they tasted pretty good.

From: Fletch36
Date: 10-Jan-19




Thank for all the responses! I also have 30" 2117s that will probably do the trick as well. Like you all say, I'll just see how the arrows that I have shoot through it and go from there. The bow isn't in my possession yet, and it's traveling via Parcel Select, so it'll probably take a couple weeks to arrive from Cali. Javelinas would probably be a lot of fun -- living in PA, I haven't seen any running around lately. If I ever get a chance to hunt in the south, I'd love to give them a try. I saw Steve shot a couple on Meat Eater and they looked like they tasted pretty good.

From: Jim Compton's Traditional Bowhunters
Date: 10-Jan-19




On most of my arrow setups I'm running at about 15 to 18% FOC.

From: Twan
Date: 10-Jan-19




the other side to getting hihg foc aside from point weight is getting you arrow shaft as short as you can. light gpi shafts also help a lot.

i just tune to a 250 or 300 grain point and try to choose a spine that wont end up being a lot longer than my draw length

I think the highest I have had was 26 percent just by doing this. not hard at all.

From: Fletch36
Date: 10-Jan-19




Okay, Twan, but what was the main advantage? 29" is as short as I can go with out the arrow encroaching on my riser.... Were you trying to get a heavier arrow overall or do you feel that there are real aerodynamic benifits from 26% FOC. I've never really had an arrow flight problem, and I do enjoy shooting longer shots -- I'm more of a shooter than a hunter, but I do hunt and if the only advantage is for hunting, I can keep this set of higher FOC arrows specifically for hunting.

From: Draven
Date: 10-Jan-19




Fletch36, when you have time to burn spend it reading this:

http://witchfordarchers.drmsite.com/resources/Archery%20Mechanic s.pdf

Archery mechanics

From: Draven
Date: 10-Jan-19




PS Take out the space between the letters in that link.

From: George D. Stout Compton's Traditional Bowhunters
Date: 10-Jan-19




EFOC is more a talking point than anything else. I think Rick Barbee did some testing that proved that. Folks should be much more concerned about perfect arrow flight and actually being able to hit what you're shooting at.

From: JRW
Date: 10-Jan-19




Several years ago someone asked me about the FOC of my hunting arrows, so I measured it: 13%. Since I've shot clean through a bull moose (and everything I've hunted smaller than that) I'm not sure what I would supposedly gain by increasing it.

If it's not broke.....

From: fdp
Date: 10-Jan-19




12% FOC is in the pretty well standard category. 20% FOC is in the HFOC(*High Front of Center) category but certainly not in the EFOC (Extreme Front of Center) category.

If you are tinkering with the FOC thing per the Ashby report criteria and your total arrow weight isn't 650 grs. or more, you are NEVER going to duplicate the results that he got.

I really think the FOC thing is way over blown since it hasn't allowed anybody to kill anything with a bow that hadn't been killed before.

From: gluetrap
Date: 11-Jan-19




imo at 63lbs. foc is not important. at 35??

From: George D. Stout Compton's Traditional Bowhunters
Date: 11-Jan-19




gluetrap, it doesn't matter at any weight. Mass is mass. I can't find a good reason why an arrow weighing 400, 450, or 500 grains won't penetrate as much as another weighing the same grains if travelling the same speed and with perfect flight, regardless of where the weight is on the shaft. Physics would affirm that.

Penetration is about arrow flight and a sharp head that begins to cut on contact. I think not much thought is given to guys who don't have good arrow flight, or don't even get to anchor when they shoot at an animal, then complain about penetration.

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 11-Jan-19




Have to disagree with you somewhat George. All arrows flex on impact when they hit the target, the more they flex, the more it reduces penetration. And, Ashby and others have shown that when the weight is forward on the arrow rather than distributed along its length, it flexes less when it hits the target. (Sort of the effect of being pulled through by the point rather than being pushed through.) Thus, it penetrates better.

Now, this is all relative, and for practical purposes, unimportant. On deer size critters, either arrow is likely to pass through so any gain in penetration that a greater FOC might provide really isn't needed.

Fletch36, 17% is just a little above normal FOC; it doesn't even reach high FOC. Agree with others, worry about getting good arrow flight. The arrow will do the job.

From: 2 bears
Date: 11-Jan-19




9 to 10 GPI with 17% foc is excellent. If you have good quiet flight don't second guess it. >>>----> Ken

From: camodave
Date: 11-Jan-19




Somewhere between about 10 and about 25%. Form trumps FOC every time. Spend your time on form, not worrying about silly stuff like FOC.

DDave

From: JRW
Date: 11-Jan-19




Orion,

"And, Ashby and others have shown that when the weight is forward on the arrow rather than distributed along its length, it flexes less when it hits the target."

It's been a while since I read the Ashby stuff, but I don't recall any actual experiments to show this. I may have missed it though. Would you be so kind as to reference it for me? Thanks.

From: fdp
Date: 11-Jan-19




As mentioned earlier, Ashby indicated there was no substantial gain in penetration until the weight of the arrow reached 650grs..

From: Glynn
Date: 11-Jan-19




http://kifaru.net/dr-ed-ashby/

Days of reading here.

https://www.grizzlystik.com/Dr.-Ed-Ashby-W26.aspx

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 11-Jan-19




JRW, check out the Ultimate Hunting Arrow segment under Ashby's 12 Arrow Penetration Enhancing Factors in the grizzlystik.com link that Glynn provided for Ashby's description of that characteristic.

Also, Easton has done a number of videos showing arrow flex at target impact. I believe I've seen some others as well, but don't remember the sources.

From: gluetrap
Date: 12-Jan-19




I don't know much about the reasons of all this stuff but my high foc arrow is a lot harder to pull out of my target than my regular foc arrow that is 10 grains heavier. may be other reasons for this?? don't know. but for those who shoot light weight bows, give it a try and see for yourself.

From: LongTrad
Date: 12-Jan-19




I like a good amount for FOC for shooting in the wind.

ashby himself did not list foc very high on what makes a lethal arrow. If I remember right I think his conclusion was that FOC helps with soft tissue penetration, not breaking bones.

From: Rick Barbee
Date: 12-Jan-19




I've shot everywhere from 9 to 30 percent FOC.

My best flying arrows, and consequently my best penetrating arrows have always come in somewhere right around 12 to 15 percent.

I'll stick with, or at least stay close to that.

YMMV

Rick

From: Longcruise
Date: 13-Jan-19




Ashby concluded that 650 grains was a bone splitting threshold wherein at that point and beyond arrows showed a decided improvement in splitting bone. That of course goes hand in hand with better penetration and doesn't suggest that arrows under 650 with high FOC are not good penetrators as well.

Like said above, "Days of reading..."

From: tradmt
Date: 13-Jan-19




Fletch36, no, it isn’t too much and I doubt you would ever see a real world difference from 10-25%. IMO, the arrow you describe is an excellent compromise between penetration potential and trajectory, assuming this is a hunting setup.

From: Mike Walker
Date: 13-Jan-19




Fletch36, Even for target archery I think you will benefit going with a heavier arrow............the 6- 7GPP arrows you were using would be very light for a wood risered bow.You may not want/need 10GPP, but I'd keep the minimum at 8GPP with this style bow.

As for the 17% FOC being too much..........not for me, but I'm talking strictly hunting.My arrows this past season had a 20% FOC and from recent experimenting my arrows for the upcoming season will have a 25% FOC.

FOC is a huge debate and no doubt any amount will work......it really depends on what you are trying to achieve.I'd experiment with different amounts and see which gives you the best accuracy. Ultimately.....having your arrows perfectly tuned is the top priority. Take care,Mike

From: B.T.
Date: 13-Jan-19




Glad I read this..regular arrows shoot through Moose. Seems good enough for me. Then the Buffalo guy says the same thing. I’m good.

From: Fletch36
Date: 13-Jan-19




I really do appreciate most of your comments. What I find interesting is that some of you assume I need to be educated on a lot of other archery related bits. I asked about one thing and you assume I don’t understand the importance of sharp broadheads, good arrow flight, consistent form, and shot placement. I feel quite confident in my ability to consistently achieve all four and if we ever meet, I’d be happy to match you arrow for arrow. The reason I don’t bother consulting you all most of the other time Is due to your inordinate respect for your own pet theories and maxims. The most useful response was the link to a very thorough examination of the physics of arrow flight, so thanks Draven. Thanks as well to all who focused on the actual question. Health and happiness to all. Keep on shooting!

From: Fletch36
Date: 13-Jan-19




Actually, as I look back it might have just been George. Sorry, as you were....

From: B.T.
Date: 13-Jan-19




You could have googled that.

From: Mike Walker
Date: 14-Jan-19




Sorry, I thought I answered your questions and was sincerely trying to help.This is why I don't post here much anymore as well.

Hi all, for those of you familiar with this, what percentage do you shoot? 25%

I have some arrows coming that work out to be around 17% FOC -- is that too much? No

I'll be shooting 29" 240 shafts with 100 gr. inserts our of a 63 lb. Super Diablo. I can play around with point weight. I think that arrow is between 9 and 10 gpp. I've been shooting carbon arrows in the 6-7 gpp range. What do you think? 240 spine will be too stiff, but arrow weight will be better as 6-7 gpp is too light.

From: Mike Walker
Date: 14-Jan-19




Maybe you meant 340 spine? If so they should be fine with heavier point weight.

From: PistolPete
Date: 14-Jan-19




Fletch - I think it’s not that folks are trying to educate you specifically, but that a debate starts and people want to weigh in. I understand your thoughts though.

I shoot 30%, which is as much as I can reasonable get. FOC is not the most important aspect of killing game with an arrow, but it does matter - as demonstrated by Ashby’s exhaustive research. I’m the type that wants to get everything possible in my favor before hunting. I understand if others are unwilling to change from a setup that works “fine”, but the fact is that more FOC makes for a slightly deadlier arrow, period. It may not make a difference on any given shot, but I’m unwilling to take that chance.

The perspective that I don’t understand, however, is the person who can’t understand why FOC aids penetration, and therefore doesn’t “believe” it works. The fact that it helps penetration, and someones understanding of why, are two different issues that are not correlated.





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