Spine calculator says stiff but tuning shows weak???

[Nativestranger]

Just an update on my arrow tuning problem. Everyone says I was overspined and the arrow was so stiff that it showed a false weak reading (nock right for left hand shooter) So I got some full length 1535 with 100 grains tip. This brought my arrow dynamic spine down a whopping 13# from 63.4# to 50.5#.

   

However I did some test at 10 - 15 yards  and getting even worse of a nock right result. The left most arrow is the uncut one with a DS of 50.5# and the rest are 29" with DS of 63.4#

   

I was wondering if I am going in the right direction and needs another drop in spine. The 29" 1535 when fletched do fly well though as you can see pretty much dead center.

[Flying Dutchman]

This is difficult to explain, but interesting... What is the width of your riser were the arrow is? 0,5"? Your drawlenght is 28? You are shooting a FF string?

Do you have possibilities to increase your pointweight, so that you have the same dynamice spine for your bow and arrow in the calculator? I am curious to see what happens then. It can also be something in your release or way of shooting.

[Nativestranger]

Originally posted by Flying Dutchman:
This is difficult to explain, but intersting... What is the width of your riser were the arrow is? 0,5"? Your drawlenght is 28? You are shooting a FF string?

Yes the riser at arrow pass is pretty narrow. I usually draw 28.75" to 29" for targer recurves but I draw 28" with this bow due to the rated draw length is measured to back of riser for grozer bows and this one has a very slim riser. I am shooting Dacron but its a very skinny 10 strand string by grozer so I used 16 fast flight instead as the speed should be closer to that. I have also tried a 9 strand ultracam with pretty much the same result but with the brace height lower by about 1/4". The ultracam string creeped badly so went back to the stock grozer string.

I did ordered some heavier points but the store left them out when shipping. I tried with both tab and glove, Static release and follow through release, upright bow. Pretty much the same result.

[Mike Brockner]

Jimmy,
Based on your second set of arrows it appears that both the fletched and bareshaft arrows from the same set are grouping togeather, and this is fine.

I would go and shoot a group of three arrows each, bareshaft and fletched and see where they group.  The most important thing in bareshaft tuning is to get both bareshaft and fletched arrows hitting the same place.  If you accomplish this you are fine.

Dont take the calculators values as "Must have" it is a tool to get you close to your suggested setup.  I shoot way over spined arrows and they fly like darts.

Check out the Shooters FORM Forum, you can get alot of help and useful info there.
Mike (fellow lefty who strugled with the calculator too)

[Nativestranger]

Originally posted by Mike Brockner:
Jimmy,
Based on your second set of arrows it appears that both the fletched and bareshaft arrows from the same set are grouping togeather, and this is fine.

I would go and shoot a group of three arrows each, bareshaft and fletched and see where they group.  The most important thing in bareshaft tuning is to get both bareshaft and fletched arrows hitting the same place.  If you accomplish this you are fine.

Dont take the calculators values as "Must have" it is a tool to get you close to your suggested setup.  I shoot way over spined arrows and they fly like darts.

Check out the Shooters FORM Forum, you can get alot of help and useful info there.
Mike (fellow lefty who strugled with the calculator too)

Thanks for the input. I will check out the form forums

[snag]

I would take off the wrapped up fletching on the "bare shafts" also. When you add weight to the rear of an arrow you are stiffening the arrow...this will give you a false reading.
Don't worry about nock left or right it is where they are grouping. Unless you are seeing the arrow flying sideways to the target of course.

[Flying Dutchman]

BTW, just watched your video, nice shooting! Inside the house also.... my wife wouldn't be glad if I did that... I don't hope somebody is holding that camera  

I am very interested in the results. In the first set-up you have a difference of 27 lbs between bow and arrow. Stu can be a little bit off, but never so much...
I can remember however talking two a guy who was an horse-bow expert, he owned more then 25 and was shooting them real good. According to his experience Stu was too low on most horsebows, making you underspined. But he mentioned 10 lbs or so and now we are dealing with 27...
Crazy stuff...

And indeed, try shooting with real bareshafts. It looks like you wrapped some paper around the feathers and  taped them. That might be of infuence too. You never know.

On the other side, when you arrows are doing the job, who gives a heck about it?

[Rob DiStefano]

spine charts, spine meters, and software "calculators" are guidelines at best.  how you shoot, your form, your tackle and all its fine points - all play a role in how the arrow will fly for you.  learn to make adjustments in tackle and form until arrows track true.

[Nativestranger]

I finally got the answer. Those arrows were actually underspined. My fletching jig arrived so I stripped of the feathers on the arrows and tested again this time with the "real" bare shaft. The results are the same as with the wrapped feathers. 29" GT 1535 with 85g tip shows only slightly weak. Full length GT1535 with 100g tip showed weaker. However I tried full length GT 3555 with 85g tip which according to DSC will be the most overspined arrow but it tuned perfectly! In the image below the rightmost nock is the full length 1535. Wierd results but gonna try the fletched 3555 with 85g points tommorrow at the range. Thank you to all who replied for your help.    

   

[Flying Dutchman]

Go on and let us know Jimmy. And let Stu know your results, it helps to get the calculator better.
And remember to take care you nocks fit right before you bareshaft!

[Jeff Strubberg]

Also, judging arrow flight by how the arrow sticks out of the target is problematic.  My experience has been that if the arrow hits the target with any lean at all, the target will exaggerate the heck out of that lean, causing you to scratch your head in confusion.

You could be very close to the right recipe with what you have.  Try either the shaft planning method with your bare shafts or shoot through some paper.  I bet you are a lot closer to correct than you think.

[Nativestranger]

Ad, those results are shot with an 8 strand D10 string with good nock fit.

[Nativestranger]

Originally posted by Jeff Strubberg:
Also, judging arrow flight by how the arrow sticks out of the target is problematic.  My experience has been that if the arrow hits the target with any lean at all, the target will exaggerate the heck out of that lean, causing you to scratch your head in confusion.

You could be very close to the right recipe with what you have.  Try either the shaft planning method with your bare shafts or shoot through some paper.  I bet you are a lot closer to correct than you think.

Good point on the target exaggerating arrow lean. I found it not accurate at all if the target is worn so I shoot at an unused spot.  Will try some paper next. But at this point I think I am happy.  Thanks again for the suggestions.

[Nativestranger]

Tested at the range today. Both the fletched GT3555 and the 29" 1535 with 85g point fly great and group well. Both are very quiet when shot from the bow.

At 15yards
 

Now let see what can I hunt around these parts.   :cool:

[Flying Dutchman]

Good shooting Jimmy. Now walk back to greater distances and see if there is some noticeable difference between both shafts. I test till 50 meters. At bigger distances differences become more evident.
At 15 yards I shoot almost every arrow well  

[Nativestranger]

You are right Ad. I did shoot abit at 25 yards. The max at my range. But I know my limitations. I am not that good of a shot at anything further than 25yards to reliably tell between the arrows.

[Flying Dutchman]

Just keep om training at 25 yards and you will be amazed  

[Nativestranger]

I will. And I can't wait till I get a proper longbow like yours.

[Flying Dutchman]

I will sell you one for € 2.500,- Delivery from stock!