Arrow penetration on moving targets

[Sharp Things]

How much (if any) penetration is lost due to game movement at the time the arrow impacts the animal???? Deer and other game will dodge, duck, dip, dive and dodge in advance of and during the arrows impact. This has the effect of changing the path and direction of the arrow shaft. This game movement applies sidewards and bending forces to an arrow shaft the wants to travel in a singular direction. Doe it result in a reduction of penetration?

If you have seen aerial, foam disks being shot with an arrow you will notice that rarely will the arrow penetrate all the way through. Is this due to the movement of the target altering the arrows intended path? Likewise we have seen video footage of game animals making fantastic, twists and turns and drops as the arrow attempts to make its way through and stories of arrows changing directions and existing parts of game animals far from where we might expect to have exited based on the point of impact. In such cases, Its not uncommon for the animal to run off with the arrow. Was this dues to energy being stripped from the arrow via a direction change?

But just how much (if any) penetration is lost due to this sudden change in forces and direction to the flight path? Can it be measured? We hoped to put these questions to the test with a target meant to change an arrows direction during impact in an effort to measure the effects on penetration.

[video=youtube;IZIdaKc83nc]https://www.youtube.com/watch?v=IZIdaKc83nc[/video]

Apply what you have seen. Formulate a hypothesis. How much (if any) penetration is lost due to the change in direction? Penetration Measurements were taken on the stationary target and then again while the target was spinning in an attempt to capture results under these two parameters.

Was penetration reduced due to the spinning target (by what percent?)

Was penetration improved due to the spinning target (by what percent?)

Was penetration unaffected by the spinning target?

 

[Beendare]

Interesting topic.

I think its a significant factor. I've seen less pass throughs on animals that flinch or move on the shot. In fact, its caused me to change up my gear [many years ago] from a fast light setup to a heavier arrow...primarily for the less bow noise= less animals flinching.

Its kind of funny, guys talk about shot location being numero uno...but then they shoot a fast/light arrow that almost guarantees the animal won't be in the same position when their bow goes off.

^Not a blanket statement....of course the above statement also hinges on other factors like distance, whether the animal is looking at you, etc.... Bottom line I style my equipment and my hunting technique....so that if I do everything right [rare...../grin] the animal doesn't know what happened on the shot.

 

[roadrunner]

Erratic arrow flight (sidewinder missile style, proposing, fishtailing, etc) is comparative to a straight linear flight path arrow and perpendicular (assuming broadside) moving target. Neither will penetrate very well.

Once shot a sloooww heavier arrow setup where speed didn't matter (tongue in cheek) and got poor penetration on a 6x bull because of a bad release (and probably torqueing of bow).

Calculated numbers being equal, whether heavy and slow vs. light and fast, either setup will result in poor penetration on a moving target (or bad arrow flight).

 

[Blockcaver]

Interesting test. Bet you see some reduction in penetration. A couple of variables that would be good to eliminate from the test are the different velocity of target as you get further from the center. It would be nice if it was kept constant, which could be achieved by shooting it on the “tread” instead of the sidewall, assuming the drill is always operating at a constant RPM. Or maybe try to use data for arrows that hit the circular line on the sidewall, ignoring others.

The other variable is the rearward flex in the target. Again this is a variable depending on where the arrow strikes the sidewall, further from the center of the target will increase the leverage and movement. Ideally this variable should be eliminated with a stiff attachment to the drill.

Thanks for posting the test!

 

[2blade]

I shot a deer last year that was broadside to me at 30 yards right before I released the arrow. I don't know if he heard the bow or saw me move or what but before the arrow got there, he spun going away from me to run off. The arrow caught him in the left hind quarter missing the bone on the outside and traveled full length up thru his chest. It was not a pass thru but the broadhead was sticking out the front of his chest about 8" or so when I found him, only went 50 yards. I have no doubt had he remained broadside it would have blew right thru him.

470gr 5mm arrow shot from a 60lb bow with a 145gr, actually 150gr, Steelforce Phathead. I'll more than likely be sticking with the same setup this year.

 

[MattB]

This is a case of the legless frog being deaf (if you happen to know that joke). When shooting a really light target, the target doesn't present enough resistance to keep the arrow from moving it, which in turn results in reduced penetration. There is certainly something to be said for an arrow suffering reduced penetration in a moving target, but the lack of penetration on a thrown target is an entirely different thing. You'd likely see a similar lack of penetration if you just set a throwable target on the ground and shoot it.

We've noted the same thing over the years shooting large MBH's on javelina. We shoot through deer with the same BH with regularity but often fail to get passthroughs on javies because they actually get moved by the arrow due to their light weight/stiff hair, and penetration suffers.