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Old 10-13-2017, 09:53 AM   #35
enewman
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Join Date: May 2009
Location: Odessa TX
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Originally Posted by samson33 View Post
KE is a marketing tool used by the archery industry. Arrow penetration capability relies on momentum. To dumb it down a little, Momentum is what keeps arrow moving after the point of impact. When it comes to momentum, there is no point of finishing returns in the realistic range of hunting arrows. Heavy is always good. Now, there are several other things to consider. FOC, Target animal, broadheads type and sharpness and bow tuned to perfect arrow flight. For Deer, there is nothing wrong with a 430 gr. arrow as long as all other factors are also being considered. Look at the Easton Hexx 330. You can put 75 gr brass insert up front, 100 gr head and weigh in around 430 gr. with good FOC. And when the time comes, shot placement is critical.

One other thing, a properly spines arrow with increased FOC, usually flies better than its lower FOC comparison.

Consider this....my wife gets pass throughs on elk with a 350 gr arrow, 25" draw and 47 lbs. It takes a good combination of all mentioned factors to get that performance for her.
Yes a good combinations. This is why the 12 penetration factored by dr ashby are a good to look at when designing arrows. And weight is number 12. So always a way to build a great arrow with out being overly heavy

TWELVE PENETRATION FACTORS

1. Structural Integrity 
The most important factor of arrow penetration is structural integrity. If any component of your arrow fails, then penetration either completely stops or is greatly reduced. 
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2. Arrow Flight 
If an arrow is not flying perfectly, then itís wasting valuable energy that could have contributed to penetration. If an arrow impacts before it has achieved perfect flight, then energy is wasted that could have contributed to forward momentum and penetration. Perfect flight is crucial; you must achieve it no matter what the cost. Pay close attention to the other factors too though or you may find yourself shooting arrows that fly perfectly but canít penetrate well at all. 
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3. Arrow FOC (Front of Center) 
Tests have shown that EFOC, defined as 19% - 30% front of center and Ultra EFOC, defined as over 30% front of center enhances penetration from 40% to 60+%. 
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4. Broadhead Mechanical Advantage 
Long narrow broadheads have an advantage over shorter wider heads. It takes less energy to push them through an animal. That is their mechanical advantage. This is second only to EFOC and Ultra EFOC as a penetration-enhancing factor. 

5. Shaft Diameter to Ferrule Diameter Ratio 
Youíll lose up to 30% of your penetration potential if the shaft diameter is larger than the ferrule diameter where they meet. Itís best to be slightly smaller in diameter than the ferrule of the broadhead. 

6. Arrow Mass or Weight 
Heavier arrows absorb more energy from the bow at the shot and heavier arrows carry their momentum better than lighter arrows, so heavier arrows penetrate better. Bow hunters should use the heaviest arrow that will deliver a trajectory they can live with. 

7. Broadhead Edge Finish 
Broadhead edges that have been honed and stropped smooth have a 26% advantage over smooth filed edges and a 60% advantage over the coarse ďserratedĒ Howard Hill edge.

8. Shaft Profile 
On all shots, tapered arrow shafts show an 8% penetration gain over parallel wall arrow shafts and a 15% gain over barrel tapered shafts. 

9. Broadhead/Arrow Silhouette 
Smooth transitions and slick arrow finishes greatly enhance the penetration potential of your broadhead/arrow combination. Broadhead ferrules with bumps or any irregular surfaces impede penetration, especially in bone. 

10. Type of Edge Bevel 
Only if no bone is encountered, then the type of edge bevel ranks 10th. If bone is hit, and more often than not it is, this factor jumps up toward the top of the list. If you canít get through the bone, penetration stops. The powerful rotational force of single bevel broadheads splits bone. Single bevel broadheads regularly turn what would be a wound into a killing shot. Note: Your arrow must be of sufficient weight and strength to drive the broadhead through and withstand the forces involved in breaching the bone. 

11. Tip Design 
In all testing where bone was encountered, the Tanto tip performed best. It resisted damage and skipped less than any other tip design.

12. Arrow Mass 650 grains and Above 
When soft tissue is hit, this factor is ranked last in importance, BUT if heavy bone is hit arrow mass will be near the top of the list. Heavy bone is almost impossible to breach unless you have 650 grains or better in mass arrow weight.
Dr. Ed Ashby
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