FOC vs. WEIGHT

[gordydog]

Roger Norris, I have found the same general results on foam, due to the smaller diameter, the carbon penetrated best(slightly). A 5|16 wood shaft with super arrow flight was second best. Even with arrows from 9.4% to 28% FOC and weight from 580 gr. to 740gr., unknown velocity, 4 different 2 blade broadheads, 12 different arrow setups. Tuning for arrow flight was the most notable factor for penetration.  Fun to play around with. Maybe a 200# pound bag a hamburger would  be a good penetration medium that is sectioned off every 8" with 1\\8" plywood. ha ha

[creekwood]

Originally posted by gordydog:
Which arrow would have greater penetrating potential?

It seems to me that the key word is "potential". Without a doubt, the heavier arrow has the greatest potential to penetrate.

[Coiloil37]

If I'm not mistaken, the benefits of efoc was more evident "after" bone was breached.  Ashby also maintains 650 grains as the minimum for reliably penetrating bone so if that's what your looking for you would probably pick the heavier arrow.

[Zradix]

Originally posted by Friend:
Just noticed that the your question stated that the 500 gn and 680 gn traveled at the same velocity.

No question - The 680 gn arrow's pentration will be far..far... superior.

X2

[swampdrummer]

Without going crazy technical, I shoot a very heavy arrow out of a relatively light draw weight bow. 640 grains out of a 43# to be specific.I'm up at 28% EFOC and with the exception of hogs out of a tree stand where the arrow was stopped by the ground underneath them, I'm getting complete pass thru's on everything I have shot in the last 2 years.

[vintage archer]

FOC is  important  buit not as important as total arrow weight. A arrow the is 650 grains or heavier aproaching the bone penterating thereshold would be the first priority of a good penetrating arrow.

FOC is part of the penetrating formula for good penetration but just part of the equation.FOC does not contribute in breaching bone unless the weight up front is on a heavier arrow then it dose nothng for the breeching process but helps after the bone is breached or penetrated

FOC is helpfull in softtissue having high FOC on
a light arrow as suggested around 500 really is not that effective

An arrow to strive for would be a high FOC 20% plus or more yet total arrow weight above 650 grains

The velocity figures that  you refer to throw me for a loop
Whie velocity is important it is not a over welming factor in the momentium formula  Momentioum is what we srtive for with heavey arrows.

[Friend]

Dr. Ashby's extensive studies have shed much light on developing a lethal arrow. Personally, I have tested the waters up to 32% Ultra-EFOC on four different set-up. Significant penetration increases have been undeniable to me and moving from 30 to 32% provided an eye opening surge in penetration. The arrow wt. increase was merely 50 grains.

Conducting your own testing may serve you well in alleviating your concerns. While an Ultra-EFOC fan, my quarry
requires less lethality and am unable to justify the excessive target replacement.

Due note that the 650 gn heavy bone threshold was substantiated utilizing water buffalo as the subject. Seems quite logical to reason that the bone breaching threshold would be considerably less for the quarry I pursue.

[gordydog]

Thanks for the input and real life set ups and results with light bows.

[foudarme]

if you can speak french I have done a complete study here:

-   http://www.blog-archerie.com/fleche-lourde-vs-fleche-legere-faux-probleme/  

-   http://www.blog-archerie.com/partie-ii-penetration-des-fleches-fleche-lourde-vs-fleche-legere-faux-probleme/  

-   http://www.blog-archerie.com/partie-iii-penetration-des-fleches-fleche-lourde-vs-fleche-legere-faux-probleme/  

-   http://www.blog-archerie.com/partie-iv-penetration-des-fleches-fleches-lourdes-vs-fleches-legeres-faux-probleme/

[gordydog]

Thanks foudarme,  great penetration chart.

[sbschindler]

on the other site a guy that goes by the name of Elknut, did some pretty good and extensive test on arrow weight and penetration. his findings showed that an arrow weigtht between 500 and 530 grains out performed heavier arrows up to 40 yards, beyond that the heavier arrows did better, all arrows were shot out of the same bow, yo might want to give it a look
 http://forums.bowsite.com/tf/bgforums/thread.cfm?threadid=408061&messages=5&forum=5#3391372