EFOC vs FOC

[Chain2]

Why if the weights are identical, is the EFOC arrow supposed to penetrate more than the other. I shoot alot of weight up front but would I be better severed to shoot a heavier arrow and a lighter point with my long draw. Keeping overall arrow weight identical. Thank you

[Rock 'N Bow]

From what I understand, given that both arrows are properly tuned, all else being equal, the arrow with more weight forward will recover from paradox quicker and penetrate deeper. Of course being that I have only hunted deer and smaller animals, I have never had any penetration issues whether using a wood arrow with a 125gr point or a heavily front loaded carbon arrow. I'm sure it is more of a concern when hunting large or dangerous game.

[ocd]

I believe that the efoc shaft will act more like it is being pulled through the target than being pushed which would have the arrow flexing as it begins to penetrate . This would cause the arrow to lose some energy due to this flexing.

[McDave]

I think the foundation for any bow and arrow combination is to have the arrow properly tuned for the bow.  What that means is that you're going to have to have a stiffer arrow with your longer draw than someone would who has a shorter draw.  If you increase the point weight, the arrow is going to have to be even stiffer.  If you increase the bow draw weight, it's going to have to be even stiffer.

I think for the reasons noted above, you will get better results for a given arrow weight if more of that weight is up front, but that is only true if you use an arrow of sufficient spine to handle it.

[Prairie Drifter]

If all your shooting is deer sized game, it won't matter. If your shooting elk sized and up, then a efoc arrow would be my choice.

[Chain2]

I was thinking that the EFOC would be like pushing a chain and although it would recover quicker, my thought was that the FOC arrow would not be as distorted to start with.

[Stumpkiller]

EFOC gives more form stability.  The heavier nose tends to stay "in flight" and it takes more force to divert it.  Whether the medium is air or tissue this remains true.  

Arrows, aircraft, missiles . . . if you move the center of gravity back they are more maneuverable.  You do not want a more maneuverable arrow.  

I would still argue that sharp and accurate is of primary importance.  It does no more good to miss an animal with an EFOC arrow than with a mere CFOC (Conservatice FOC).  Shoot what you can shoot well and keep the head sharp.  Good arrow flight probably does as much for penetration by eliminating side drag as EFOC does.  If you can do both?  Best of all worlds.

I haven't calculated mine as I know my arrows work, have worked since the 1930's, and are more than capable of dropping the whitetail I hunt.  If I was after larger game I'd be more concerned.

[Chain2]

Thank you. I guess I was trying to fix something that isn't necessarily broken....imagine that. Thanks Guys.

[gonefishing600]

Here read this.

 http://www.arrowtrademagazine.com/articles/sept_10/Sept2010-TraditionalFocusExtremeFrontOfCenter.pdf

[Chain2]

Wow. I didn't know that 650 is the magic number. Thank you for sending.

[LittleBen]

If you don't hit bone, it shouldn't matter much at all because the arrow isn't going to flex much at all on impact with muscle/hide/lung.

If you hit bone the arrow will decelerate very rapidly, this will cause flexing of the shaft. The more of the arrow's mass is on the impacting end, the less the shaft flexes all other things being equal (dynamic spine, arrow mass, speed etc.)

In other words, an arrow with 0% FOC acts equally stiff during acceleration and deceleration (assumign the rate of acceleration and deceleration is the same). An arrow with very high FOC acts fairly weak in spine when being shot from teh bow, and very stiff when decelerating on impact.

I wouldn't imagine that this really matters that much, but what the hell do I know ... I certainly haven't been spending my free time shooting through buffalo ribs. Apparently at least one guy has and says it matters.

[JamesKerr]

Originally posted by Stumpkiller:
EFOC gives more form stability.  The heavier nose tends to stay "in flight" and it takes more force to divert it.  Whether the medium is air or tissue this remains true.  

Arrows, aircraft, missiles . . . if you move the center of gravity back they are more maneuverable.  You do not want a more maneuverable arrow.  

I would still argue that sharp and accurate is of primary importance.  It does no more good to miss an animal with an EFOC arrow than with a mere CFOC (Conservatice FOC).  Shoot what you can shoot well and keep the head sharp.  Good arrow flight probably does as much for penetration by eliminating side drag as EFOC does.  If you can do both?  Best of all worlds.

I haven't calculated mine as I know my arrows work, have worked since the 1930's, and are more than capable of dropping the whitetail I hunt.  If I was after larger game I'd be more concerned.

Well said.

[Friend]

Much valid testing has been decidedly conducted and many discussions continue with regard to the attributes of EFOC and Ultra-EFOC.  Appears as humans, we may be swayed by what one person states vs another or may be heavily influenced by effective communication regardless of the validity of the information conveyed.

There is no better way to build your own confidence level than to conduct some reasonable testing on your own. Tune one shaft  that has Hi FOC in the 12 to 19% range. Then tune one shaft in the Hi EFOC range to Ultra- EFOC(28 to 32%).
Both shafts total weight should be similar. Then conduct your penetration test on a reasonable medium. If a dial caliper is required to deduct the differences, then one is likely wasting his time.

Conducting your own test will unquestionably serve as a valid confidence builder.

[stujay]

Thanks gonefishing for the article link. Very informative.

[katman]

Chain, if you already have an efoc arrow well tuned I think you would do well to stay with it and keep broadhead sharp.

[drewsbow]

It was written some where that an efoc arrow is like a rock with yarn tied to it . The rock being the heavy head and the yarn being the arrow , where you throw the rock the yarn follows. Also the way I look at it is that the heavy head pulls the arrow through game versus the heavy shaft the arrow is pushing the arrow through if that makes sense .

[Chain2]

I am starting to get it. I am shooting a GT 55/75 full length w/50gr brass insert and a 250 gr head. I think GT has it around 21% FOC. I think it is around 608 gr or so. Flies good. I will stick with it or maybe experiment with 50 gr more when I get me new Sasquatch. Thanks Guys

[FJTOYMAN]

FWIW
I shoot CX 250s out of my 57 lb long bow. They are 31.25" balance at 21" which gives me a 17.2% foc. Total weight is 592 grains. 2 blade single bevel tusker heads that are 200 gns and shaving sharp.
I've shot 3 bull elk. All my arrows except for the one on my bull in my avatar had the broad head pass completely through making an exit hole.
I hit my biggest bull about 2" above his brisket and split ribs going in and out. The tip if the broad head just cleared the last rib but didn't cut the skin. Fortunately I pierced the heart and he only went about 20 yards. I can't find my picture right now but you could clearly see the "S" split in the rib Dr Ashby talks about.