Wood arrow spine test

[Gordon Jabben]

I made up eight cedar arrows that were identical in looks but were spined from 52# to 92# in 5# incumbents, 52 57 62 and so on.  I numbered them at random. The weights were within 10 grains. I made these arrows to see which flew better without taking the chance of breaking them which happens sometimes bare shafting. Took them out and shot good groups, at least for me, with my 55# r/d bow at twenty yards and I didn't notice any of them flying all that poorly.  I'm sure the 5" feathers helped. I had a couple friends shoot them without telling them about the difference in spine and they also shot nice groups and complimented me on my new arrows. One was shooting a 60# r/d longbow and the other a 60# Hill style bow. After some shooting we noticed the Hill style bow did not shoot the #4 arrow as well and it turned out to be the 52# arrow. I was surprised by these results and was wondering if anyone else had tried this.  Next will be the real test when I try broadheads on them.

[Shadowhnter]

Depending on arrow design and tip weights, recovery can happen extremely fast. I had made some arrows up recently, that I knew should be overspined for my bow by a fairly substantial margin. The arrow seemingly flew great, hitting right where I was aiming, very consistently. As I shot it though, I noticed that it seemed pretty sensitive to my release, and anything less then absolutely perfect, id notice a slight wagging. EASY to overlook. So I shot through a paper tuner at close distance.....ugh. Huge tear showing massive stiffness, yet for the most part, my eye couldnt pick it up. I then bare shafted it....you got it....very stiff as well. I increased 50gr of head weight to begin seeing a change take place, and was still a bit stiff. With feathers alone, because of my arrow design, it was very difficult if not impossible to see without proper testing.

I took an average penetration measurement with the fletched stiff arrow in my target. Later I did the same with the properly tuned and spined arrow, being very close in weight. The tuned arrow got an average of 1 1/4" better penetration in dense foam. There is a difference,  trust me.

[Fletcher]

That is why I paper tune my wood arrows.  Fletching can get a hold of an arrow pretty quick and my eye just can't catch the arrow coming off the bow.  Shooting thru paper from very close, 6-10 feet, very clearly shows what the arrow is doing.  Once I get the spine figured and nock points set for a hole or small tear, I can shoot broadheads right along side field points with no issues.  On a good release no wind day, I can see three pounds spine in the paper.

My test arrows are marked with the actual spine and fletched with three 4" feathers.

[Orion]

I don't find your results at all surprising.  The purpose of feathers is to straighten out the arrow.  Most bows will shoot a range of spines quite well if the arrows are fletched.

Sure, we can tune to the nth degree, but if the feathers straighten the arrow quickly, even if the spine would be a little off as detected by bare shaft tuning, so what.  The arrow still goes where you want it to go.

I've been at this a long while, more than 60 years, and from my experience watching others shoot, most don't have form consistent enough to benefit from bare shaft tuning.  Luckily, it's not necessary.

[Gordon Jabben]

Thanks Orion, that's the conclusion I came up with.  My groups are about the same with my arrows that are within 5# spine of each other and the ones I made up that have a 40# spine difference. I shot this group at just over 20 yards at a water bottle cap with the 52#-92# shafts and it is about what I would expect from a matched set of arrows although some of the arrows have not fully straightened out in this distance. I probably won't worry quite as much about arrow spine as I did in the past.