# Arrow Straightness versus Accuracy Test Results



## Rick! (Aug 10, 2008)

Here's something I found on an Australian archery forum. 
Looks like somebody spent some serious time on a Hooter Shooter...

_Archers by and large are a frugal bunch that will go out of their way to extract improvement in their scores with the least amount of investment. Arrow straightness, as sold by each arrow vendor, provides a perfect subject for the “is it worth it?” experiment. There are myriad anecdotal instances of “no difference” for uncontrolled testing of arrow shafts from .001” straightness to .003” to even .006” as produced by the manufacturer and for us, we just don’t think it’s that simple of an answer. A few of us from across the globe got the bug to answer the accuracy versus straightness question for ourselves and we’ll share the results for those that wish to read the rest of this summary.

We tested the group size of several sets of arrows with defined levels of straightness; .001” or less, .003” and .006” at the center of the length of the shaft. Then, we handed a passionate archer in Australia 18 new Easton 2315s and some gas money to burn several weekends at an indoor archery range. He ran them through his Hooter Shooter at 25 meters and took careful measurements and notes during the process. He also spent considerable time fletching the arrows, both straight (0 degrees) and angled straight using two moderate angles to evaluate their respective group sizes. Once all the data was gathered, processed, and compared with some arrow flight programs the results of the experiment were composed and reviewed by the group.

The results illustrate pretty clearly that straighter arrows group tighter than the less than straight arrows. In fact, the groups with the straightest shafts with angled fletches shrank over 40% when compared to the .006” fletched shafts. Since no serious archer ever has arrows that are of the .006” type, the .001” to .003” shaft comparison was still rather significant; a 10% to 25% group size reduction was observed with the straightest arrows. The “why” answer to the POI change on the lesser straight arrows can be attributed to the imperfect alignment of the bow’s power stroke to the arrow’s center of gravity (CG or CofG). With fletched arrows, this is most prevalent prior to the arrow completing its first rotation. The second most important result is that your favorite flavor nock may not be the most accurate one. This effect was tested twice in the experiment and at least once by some of the group members with positive results. In summary, arrow straightness has a direct effect on the group size of a set of arrows and using a nock with the shortest load path from string input to the arrow shaft provide the basis for the tightest arrow groups using a shooting machine.

The rest is up to you.

For more in depth information, our research has been submitted for publication with the title *“Effect of arrow shaft straightness on arrow grouping.”* _


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## vito9999 (Jun 30, 2009)

Nicely done. Now were these all full length?


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## lees (Feb 10, 2017)

How long do your favorite arrows stay at .001" straightness too is another variable in the equation. Especially aluminums from shooting them over and over are bound to leave .001" after a while. I still have 4 totally ratted out goldtips in my quiver that shoot the same as always and they're my favorites that are always my #1 in a tournament, but I can tell you they're not straight anymore to .001" tolerance without even measuring them. Or maybe I'm not that good of a shot yet . 

lee


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## aread (Dec 25, 2009)

I'd like to read the whole paper on this. The brief summary above did not mention how the researchers accounted for spine. Having spine matched from arrow to arrow and matched to the bow will make significant differences. Did they measure nock alignment, did they nock tune, etc. I'm sure that they covered these things.

Rick McKinney has an article floating around that basically summarizes that spine consistency is more important than straightness. This was when he was on the Olympic team, so he probably didn't have any .006 arrows to test.  I seem to remember that at 90 meters, .001" variation in straightness equals 1" difference in POI. I'll have to look up his article. Note: this was with Olympic recurve bows. With all recurve and long bows, spine is one of the most important factors. It can easily make a difference of a couple of feet, even at shorter distances. It would probably be quite different with a compound bow. 

Do you know where I can get a copy of the paper?

Allen


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## vito9999 (Jun 30, 2009)

I was going to mention spine variability but did not want to open that can up since OP only mentioned straightness, that is why I asked about arrow length. My thoughts that unless each arrow was nock tuned from bare shaft there would be no true baseline to start from.


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## taz00 (Jun 28, 2015)

The paper has been submitted for review to a scientific publication.
Until it is published all the details of the paper are not likely to emerge on an open forum.
However I will contact the research group and find out wha details could be published until then.


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## babyg (Jul 16, 2002)

Interesting...


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## j.conner (Nov 12, 2009)

taz00 said:


> The paper has been submitted for review to a scientific publication.
> Until it is published all the details of the paper are not likely to emerge on an open forum.
> However I will contact the research group and find out wha details could be published until then.



Which journal was this submitted to?


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## AUSSIEDUDE (Apr 17, 2009)

I read a report from Easton many years ago that gave the results of testing their own arrows for accuracy when shot through a Hooter Shooter with a compound bow. Their test showed a difference in group size but it was so small up to .005 that their comment was that no ordinary archer would notice a difference. The .008 arrows tested showed a bit more spread, about half an inch groups from memory, the majority of archers probably wouldn't notice any difference with those either. I have seen new guys at our club switch from low quality arrows to premium arrows and they have said it has made a big difference to their accuracy even though they struggle to shoot 3" groups at 20yds. I still buy premium arrows but I am probably wasting my money.


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## Rick! (Aug 10, 2008)

AUSSIEDUDE said:


> I read a report from Easton many years ago that gave the results of testing their own arrows for accuracy when shot through a Hooter Shooter with a compound bow. Their test showed a difference in group size but it was so small up to .005 that their comment was that no ordinary archer would notice a difference. The .008 arrows tested showed a bit more spread, about half an inch groups from memory, the majority of archers probably wouldn't notice any difference with those either. I have seen new guys at our club switch from low quality arrows to premium arrows and they have said it has made a big difference to their accuracy even though they struggle to shoot 3" groups at 20yds. I still buy premium arrows but I am probably wasting my money.


With all due respect, a story, or a remembrance without an actual report or research paper is just an anecdote of which there are myriad examples in archery.


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## mfr22 (Feb 24, 2005)

I think I will just keep shooting the .001's, then I don't have to worry if the "theory" is right or wrong. I would like to see this done with broad heads though because mine definitely seem to shoot better with the straighter arrows.


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