Arrow build advice

[Christopher.Reed]

My draw length is 29". I tend to agree that longer DL likely makes tuning trickier and more sensitive to arrow spine (amongst other factors).


I'm surprised that a .065" change in static spine (assuming that's the only thing you changed) would cause a 6" change in tail behavior. Did you ever get either arrow tuned? If so, did you try the other arrow again afterward? Personally if I got a 300 spine arrow tuned then switched to a 235 spine (at the same length, front/rear weight distribution and same bow specs/settings), I would expect it to tear/fly the same as the 300.


That's a good example of compound bows being able to handle a fairly wide range of spines. You added 10 lbs of draw weight and the same arrow still flew fine.


A longer insert will stiffen dynamic spine to some degree. Whether or not a 2" insert really makes an arrow "behave" a full 2" shorter, I don't know (neither does Archers Advantage or Pinwheel BTW...spine calculators just give approximations based on empirically derived rules of thumb and can't account for every variable in the bow-arrow-shooter "equation").


Dogmatically following the flawed "tail left = too weak, tail right = too stiff" advice can also result in compound shooters wasting time and money. "Check My Spine" threads full of posts laboring over a half inch here and 10 grains there are common on this forum and others when in reality, arrow spine isn't that critical with a compound bow. If I see a horizontal discrepancy in my arrow flight, I check my centershot then adjust cam position/lean then adjust rest windage (if necessary) before I even think about adjusting dynamic arrow spine.

As you mentioned, archery is highly personal and there are many ways to skin the cat. To each his own...if it works, it works. Good discussion.

For confirmation, the arrows referenced above used the same components with the only difference being the GPI and the paper tears which nock tuning had a negligible impact on.

I built several arrows for experimentation with the new bow and the only one that shot bullet holes at center shot was a 710g 200 spine, and the 235 which I upped to 700g had a 1/16”-1/8” tear. These results challenged my assumptions as the lighter 235’s should have produced bullet holes given my understanding.

Regarding quantifying the spine impact of the HIT systems length; I can’t think of a way to test it other than knowing it has an impact of which the degree is certainly debatable. In my circumstance, the HIT was 3.5” or 4” I believe (can’t specifically remember at the moment) and I simply changed the C2C length in AA until it reflected the real world arrow flight I was observing which was 2”. That methodology certainly won’t hold up to any level of rigor but it was noteworthy to me.

I then built an aberration of a 300 spine with 325g up front and a 4.5” HIT calculated at a full 4.5” shorter C2C which was “optimal” according to calculators and was a complete disaster. This proved, to me, that the HIT’s impact was obviously not 100% of its length.

I completely agree with compound bows having a range of acceptable spines, I simply disagree with “no such thing as an arrow too stiff” which is truly dogmatic.

Thanks as always for the input!


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[5MilesBack]

That is interesting, as I have seen tail left/right pretty dramatically.

Prior to a limb developing two splinters I was shooting 75lbs at almost 33" draw. I have shot 200's, 250's, 300's, and 340's out of that and never saw anything like you described with left/rights. Here's an old pic of a 200, 250, and 300 spine arrow with different fletching from 20 yards out of that bow.

 

[Christopher.Reed]

Prior to a limb developing two splinters I was shooting 75lbs at almost 33" draw. I have shot 200's, 250's, 300's, and 340's out of that and never saw anything like you described with left/rights. Here's an old pic of a 200, 250, and 300 spine arrow with different fletching from 20 yards out of that bow.
View attachment 559618

Interesting, if there was no tuning between spines, there goes the power stroke theory. Could certain bow configurations be more sensitive to spine?


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[5MilesBack]

Interesting, if there was no tuning between spines, there goes the power stroke theory. Could certain bow configurations be more sensitive to spine?

I know that there are some bows that are more sensitive to spine, but in some cases that was due to nock travel. I've heard of some of those bows always having a really high tear that they couldn't clear up until they tried really stiff arrows. But that seems kind of like a band aid to an excessive nock travel problem to me.

I would also think that depending on where the stiffer side of the arrow is, that that could cause some inconsistencies in where arrows are hitting. But that's what nock tuning is for.

On the other hand, I might be completely wrong because I was just tuning my "new to me" Traverse yesterday with top hats and had to use the widest one on the top left (left handed) to get BS's and fletched close. However, with my 250's the BS's are still a touch left of fletched with a slight nock right, but my 200's are nock left and touching the fletched. I'm sure every bow can be different. But I also have 200gr up front on the 250's and only 141gr up front on the 200's. I just keep tweaking until I get everything perfect. And this is just the 20 yard stuff........60 yard BH tuning will come later.