KE

[Brandon Pattison]

Has anyone ever done a penetration test on different weight shafts? I just shot a 340 and a 300 spine at the same target and the 300 went in farther. It could be coincidental but it got me thinking. Assuming your two groups of arrows shoot well out of your bow, what have you observed?

 

[OR Archer]

I personally like a heavier arrow but the arrow still needs to match the bow ie spine. I have a short draw so Ill sacrifice some speed for a better penetrating arrow. I currently shoot Easton Injexion 330's for a total arrow weight of 418gr. I tried the 400's and they shot and tuned great but came up a little to light for physical weight for my liking. The 330's are a bit heavy on spine but still work well. Its the momentum that the heavy arrow produces that makes them penetrate better not the KE and that's what I'm after.

 

[ontarget7]

Has anyone ever done a penetration test on different weight shafts? I just shot a 340 and a 300 spine at the same target and the 300 went in farther. It could be coincidental but it got me thinking. Assuming your two groups of arrows shoot well out of your bow, what have you observed?

Testing into a target is not really a fair assessment but in the big picture the heavier arrow will have more momentum, thus penetrating deeper.
The most important thing is the right spine and tune that leads to the best possible accuracy to the shooter. With bows we have today we have plenty of penetration so I focus more on my tuning and the best dynamic spine for my overall accuracy down range

 

[Ethan S.]

...Its the momentum that the heavy arrow produces that makes them penetrate better not the KE and that's what I'm after.

I totally agree with this. It seems most people are always trying to get the highest KE possible, but I think momentum is more important for hunting. If your bow shoots the stiffer/heavier spine good then I would say use the heavier arrow.

I also like a heavier arrow because your bow will shoot quieter.

 

[Brandon Pattison]

Maybe the title should have been Momentum. Regardless, has anyone done any testing?

 

[justin davis]

Heavy arrows rule

 

[jmez]

Ed Ashby has done a ton of testing. A lot of good stuff on this site that will answer all of your questions.

http://www.tuffhead.com/education/education_main.html

 

[keep]

All my testing has been done one animals and they seemed to like the heavier arrow less but now that I think of it they never really enjoyed the lighter one.

Not that it helps but when I increased my weight by almost 80gr I noticed a pretty good difference on penetration when shooting out back. I knows its not scientific but could see a difference.

 

[Brandon Pattison]

Ed Ashby has done a ton of testing. A lot of good stuff on this site that will answer all of your questions.

http://www.tuffhead.com/education/education_main.html

I have read all of Dr. Ashby's stuff as I shoot stickbows too. However, and a big however, you have to hit your mark to kill anything. I feel getting it there is much more important than numbers. I used to shoot super heavy arrows only to have my trajectory look like my son throwing a shot put. Fred uses 125 grain heads on the end of a 400 spine. He's a slammer.

 

[jmez]

There is an upper and lower limit to everything. Momentum and or KE isn't the end all be all. But as a rule a heavier arrow is better than a lighter one. Your bow will be quieter, more efficient, more accurate and terminal arrow performance will be better.

As you said it has to go in the right place, and that works both ways. Trajectory like a shot put through both lungs beats trajectory like a .220 swift through the paunch. Slow hit is better than a fast miss but a fast hit is also better than a slow miss.

You can maintain adequate speed and still have performance. Usually, when people are considering lighter arrows it is because they are playing the speed game. Usually a bad idea.

 

[Coyote Commander]

Momentum is the name of the game.

My "heavy, slow arrow" KE is not that impressive compared to the "light and fast" arrow guys. But my momentum (and penetrative abilities) blow the light arrow crowd out of the water.

In the era of the modern laser rangefinder, I dont see a need to strive (especially at the expense of arrow weight) for ultra flat trajectory. Sure, flat shooting is great, and ill take it if I can get it, but not at a dramatic expense to arrow weight.

Ive also tested the skinny vs. outsert sized shafts. Many think the extra penetration they gain with the skinny shafts is due to less friction due to the skinnier shaft. I dont believe this. (Friction on the shaft in a live target is negligible, muscle and tissue is under tension in a live animal, when you cut it, it recoils back, also, you have a lot of fluid in the body with lubrication properties). I firmly believe the added penetration of the skinny shafts comes from their weight. Compare like spined shafts, and the skinny shafts are thicker walled and heavier, anywhere from .7-1.2 gpi's heavier than their standard diameter brethren. Its the weight, not the diameter.

 

[Rick Leathley]

Has anyone ever done a penetration test on different weight shafts? I just shot a 340 and a 300 spine at the same target and the 300 went in farther. It could be coincidental but it got me thinking. Assuming your two groups of arrows shoot well out of your bow, what have you observed?

I want to point out the Arrow spine has nothing to do with an arrows overall weight. Spine is simply the amount of flex or how stiff the arrow shaft is. My 250 spine Victory VAPS are much lighter then the 340 spined Easton FMJ I used to shoot.

There is no debate that a heavy arrows out penetrates a lighter arrow.
That said there are some other factors that come into play with penetration. Namely FOC and under spine arrows.

I believe that if you had 2 arrows that weighed the same but one arrow has a higher FOC and a stiffer spine. That the High FOC and stiffer spine arrow is going to have better penetration.

Arrows not only flex at when released from the bow but also flex on contact with the target. That arrow flex translates to lost energy. lost energy = less penetration.

 

[Coyote Commander]

I want to point out the Arrow spine has nothing to do with an arrows overall weight. Spine is simply the amount of flex or how stiff the arrow shaft is.

That is not entirely true.

Compare a 300 spine to a 400 spine in the SAME shaft, and the stiffer spine is ALWAYS heavier.

If the outside diameter of the shaft is to remain the same diameter through all spines within that model, the heavier spine arrows have to have a thicker wall to make them stiffer, hence, they will also be heavier.

Now there can be variances from manufacturer to manufacturer, and when comparing different OD shafts. But if the OD is to remain the same, the stiffer shafts are always heavier.

 

[Rick Leathley]

I agree. My point was not to confuse arrow spine as a definition of arrow weight. An Easton FMJ in .400 spine Has roughly the same Grains per inch as my VAP's in a .250 spine.