Bowhunter Arrow Test

mez · 10-03-2003, 11:32 AM

Have any of you guys seen the latest issue of Bowhunter? Dave Holt did an extensive arrow test comparing penetration of various broadheads and comparing KE vs momentum as related to penetration. It was an interesting read and the results surprised me a little. My take was that there is not much difference in penetration between cut on contact, chisel point, and pyramid point broadheads, all other factors being equal. KE is more important than momentum as related to pentration. Settle down Arthur, I didn' t do it.

I wish he had/would have applied some statistics to the results. IMO the results are worthless without them. What is your guys takes, thoughts, opinions?

Arthur P · 10-03-2003, 12:03 PM

I haven' t read the article but it sounds like nothing new. They' ve been printing that ' KE is more important than momentum" drivel for a long time. It' s just as big a lie now as it was the first time they told it. If you' ve read Ashby' s study, he goes into great detail on why KE is NOT the prime factor in penetration, BY THE SCIENTIFIC DEFINITION OF THE TERM.

Now, if you take an arrow of given weight, and shoot it from two bows, one shooting it at 220 fps and the other shooting it at 270 fps, you get increases in BOTH KE and momentum. You put up bigger KE numbers with speed than momentum, and since speed sells and lines their wallets, that' s the term the industry insiders want everyone to believe is THE thing.

See, if you take a 350 grain arrow and shoot it at some 300 fps, you get around 70 ft lbs of energy. My longbow shooting a 580 grain arrow at 185 fps only puts out 44 ft lbs. Now if KE was the determining factor, why would my arrow pass thru a 350 pound feral hog, just as easily (if not moreso) as the 350 grain arrow? My arrow carries .4822 lb secs of momentum. The 350 gn arrow carries .4719 lb secs.

Two arrows that will achieve pass thrus. The slow, heavy one carries 37% less KE than the light, fast one. The light one carries only 2% less momentum than heavy one. It' s momentum that is the common factor, not KE. Just looking at that example and using a dash of common sense would have to tell you that Holt' s opinion (and a heckuva lot of other writers as well) of KE being the #1 factor is a bucketfull of hogwash.

But isn' t it a lot more impressive saying your bow is putting out SEVENTY FOOT POUNDS of KE rather than saying your arrow is carrying .4719 pound/seconds of momentum? They' re baffling you with BS because they can' t dazzle you with the truth.

Just remember, it' s the little unassuming number with the decimal point that you really want to watch closely, especially when you know your bow is not whacking out gobs of KE.

Deleted User · 10-03-2003, 12:32 PM

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Arthur P · 10-03-2003, 12:39 PM

Sure I could! Would that make it more impressive? LOL

Rangeball · 10-03-2003, 12:48 PM

Mez, out of curiousity, what was the target medium Holt was using to measure penetration?

mez · 10-03-2003, 01:09 PM

Styrofoam, ethafoam, a green beef hide stretched over raw meat. Arthur, I may be misunderstanding this. In his momentum test the KE was the same for the two different arrows. He had a light arrow and a heavy arrow then shot them throgh a chrony at different speeds until they both had the same KE, which I belive was 50. His conclusion at identical KE the heavier arrow, which would have more momentum, did not outpenetrate the lighter arrow.

Arthur P · 10-03-2003, 02:09 PM

Did he do the reverse test and set the two arrows up to shoot the same momentum? If he didn' t, he neither proved nor disproved anything.

How many times did he repeat the experiment? Did he get identical penetration ONCE and call it good or do the experiment 100 times?

How much weight difference was there between the two arrows? Enough to make a significant difference in momentum or was the difference as insignificant as the difference in penetration he found? (I saw one test like this where the difference was a whopping 50 grains. Whoopee.) Was the heavier arrow the same size, brand, model and finish of the lighter arrow? Was it weighted to make it heavier and, if so, how was it weighted to avoid screwing up FOC and spine? Did he use the same size, weight and configuration point on both arrows?

Did he shoot the arrow from identical bows of different draw weights or did he adjust the poundage on the same bow to get equal KE? Was the bow specifically tuned to shoot the heavier arrow or did he just fling it without doing any tuning at all?

Was the foam he used certified as completely uniform in consistency - or did he go down to Hobby Lobby and buy the cheapest old lumpy stuff they had on hand?

That' s always the problem with these magazine tests. They leave too many unanswered questions (that too many people don' t know to ask), don' t account for anywhere near enough variables, and then make grandiose suppositions and conclusions with little or no verifiable and repeatable supporting data. But the undeducated accept it as Holy Gospel and repeat it to all their friends, then those friends repeat it to all THEIR friends, so another myth is created. Or, in this case, reinforced.

Rangeball · 10-03-2003, 02:42 PM

Art, reads like one HELL of a start for a letter to the editor...

Arthur P · 10-03-2003, 02:51 PM

Yeah, but would they print it.

Rangeball · 10-03-2003, 03:02 PM

There' s only one way to find out

In this electronic age, a little cut and pasting then email could go a long way pretty easily.

How bout what you said, then throw down the gauntlet and challenge them to re-do the test to your specs...

I' d pay big money for a copy of THAT test