Arrows inconsistent, spine issue?

[1woolie89]

Hey guys been awhile since I posted, anyway I’m having some grouping issues with new arrows I built and have been trying to tune. Im having lefts and rights even at 20 yards doing absolutely everything I can think of for form and “surprise release” I’m wondering if I’m under spined.

Bow and arrow specs:
Bow:
Prime Centergy 65#
29.5 inch draw
Fast eddie xl 2 pin
Hot rod stabs
Drop away rest
Arrows:
Black Eagle Outlaws 350’s @29 inches
Brass inserts
4 fletch aae max stealth with 5 inch wrap
Total grains: 460
Spin checked the arrows they seem fine,
Don’t have access to paper tuning atm so can’t see what way it may be tearing. Any thoughts or ideas? Thanks! -Will

 

[Jimbob]

Did you leave any bareshaft to shoot?

Do you have some fixed blade heads? Install those make sure they spin perfectly and see how they shoot.


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[wayoh22]

I think you need to be closer to a 300 spine

 

[Silentstalker]

I think at 29” your probably under spined but until you paper tune it you will play the “might be” game for a while.

Get a box and cut out a large window to shoot through and tape some paper over it or build a paper tuner with PVC pipe cheaply if need be.

Either way you will get solid answers by paper tuning.

What you’re describing could be an issue with your rest/arrow too.

 

[1woolie89]

Did you leave any bareshaft to shoot?

Do you have some fixed blade heads? Install those make sure they spin perfectly and see how they shoot.


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I have spun them with Trypans, and Magnus stingers there spinning good for 005 shaft. No bare shafts left lol should have left one.

 

[1woolie89]

I think at 29” your probably under spined but until you paper tune it you will play the “might be” game for a while.

Get a box and cut out a large window to shoot through and tape some paper over it or build a paper tuner with PVC pipe cheaply if need be.

Either way you will get solid answers by paper tuning.

What you’re describing could be an issue with your rest/arrow too.

Thanks I appreciate the reply I’ll be trying this!

 

[Beendare]

I shoot about the same spec as you...and I shoot 300's

Assuming your arrows spin true, many things would explain your problem ....under spine, form inconsistency, fletch contact, loose nok, the arrow nok not contained on the string. ..to think of a few.

A cheap and easy paper tune freestanding frame can be made from PVC pipe [3/4" min, bigger pipe is better]
about 20' pipe, 2- 90s, 4- T's.

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[Ranger313]

How much weight are you shooting up front? Likely a weak spine issue IMO.

 

[1woolie89]

I shoot about the same spec as you...and I shoot 300's

Assuming your arrows spin true, many things would explain your problem ....under spine, form inconsistency, fletch contact, loose nok, the arrow nok not contained on the string. ..to think of a few.

A cheap and easy paper tune freestanding frame can be made from PVC pipe [3/4" min, bigger pipe is better]
about 20' pipe, 2- 90s, 4- T's.

______

I will build a paper tune stand that’s good idea, I have tried a few things but it seems leaving to underspin as I have 140 grains upfront.

 

[1woolie89]

How much weight are you shooting up front? Likely a weak spine issue IMO.

142 grains up front 100g broad 42 grain brass insert.

 

[1woolie89]

Appreciate all the replies guys, I will be getting a paper tune station built and post results.

 

[MattB]

Combine a squarish medium-sized cardboard box, a piece of news paper and 4 small pieces of tape and what do you have? A Homemade paper tuner.

 

[1woolie89]

142 grains up front 100g broad 42 grain brass insert.

Correction: 150 grains upfront the brass is 50 grains.

 

[Ranger313]

Copy, from what I’ve seen with my equipment I’ve usually had to jump up to a stiffer spine when running more weight up front as it weakens the arrow. Not gonna beat the paper tuning to death but as others have stated, it’s essential! Good luck and let us know what you come up with.

 

[Samdemarais]

Hey guys been awhile since I posted, anyway I’m having some grouping issues with new arrows I built and have been trying to tune. Im having lefts and rights even at 20 yards doing absolutely everything I can think of for form and “surprise release” I’m wondering if I’m under spined.

Bow and arrow specs:
Bow:
Prime Centergy 65#
29.5 inch draw
Fast eddie xl 2 pin
Hot rod stabs
Drop away rest
Arrows:
Black Eagle Outlaws 350’s @29 inches
Brass inserts
4 fletch aae max stealth with 5 inch wrap
Total grains: 460
Spin checked the arrows they seem fine,
Don’t have access to paper tuning atm so can’t see what way it may be tearing. Any thoughts or ideas? Thanks! -Will

I would imagine you are under spined. I shoot same bow and draw weight and cut my 300 Spartans to 28 inches and they tune out well.

 

[Billy Goat]

I think you are definitely underspined, but I don't think that's giving you left and right impacts. I have shot setups that are way underspined and I can still have very consistent impacts, with field points.

Probably something you are doing with your release. Left/right can be from grip, face pressure, and a slew of other things. Something as simple as leaning in with your nose a little can push the string. That generally produces an up or down, but if your string is on the side of your nose it can create left and right.

Don't rule out fletching contact.


Not saying the spine wouldn't do it, might be nock tuning would clean it up. But you can get by with a pretty weak spine and field points.

 

[Planopurist]

My specs are very similar, 29/63. I shoot a 123 gr. up front on a .340. I’ve known I was borderline too weak, but I’ve gotten good results with this build. I’m pretty diligent with my arrow builds. That being said, I’m moving to a .300 and about 150-175 gr. up front, and shortening my arrow to about 28” ctc.

Paper tune is very important. I’d check every arrow’s tear. Have you numbered your arrows to see if the fliers are consistent? You might then nock tune them to see if that helps your tear and grouping.

If you still can’t tune the tear (or inconsistency) out, take 3-4 pounds off the bow and everything. If it cleans up, that would suggest an underspined arrow at 65 lbs.


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[Samdemarais]

I would imagine you are under spined. I shoot same bow and draw weight and cut my 300 Spartans to 28 inches and they tune out well.

I’m at 28.5 draw * as well.

 

[Kcole1987]

check your rest timing if its a drop away. you may be getting rest contact. small chance it could be a spine issue at that close distance, but it is possible.

 

[Beendare]

Someone mentioned a form thing with your release...dont rule that out.

FWIW,
I primarily shoot a stickbow now...but I can tell you this:

Way back, I did a little test with my compound and release. If I pulled harder into my face vs pulling more in line ( straight back) I could turn a bullet hole tuned arrow into a 1 1/2” tear.

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