Spine calculator says stiff but tuning shows weak???

[Nativestranger]

I am in the process of tuning arrows for my 43# Grozer Assyrian bow. The arrows I am testing are 29" GT 1535 trads with 85 grain tips. I am left handed and consistently getting the result shown below:

     

This indicates shaft weak? However Stu Miller DSC shows that I am grossly overspined!

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[IMG]http://farm9.staticflickr.com/8502/8297235228_d648320222_b.jpg[/IMG]So which is right? I can get straight flight and good groups at 10-15m but shooting from a closer distance around 5m both unfletched and fletched arrows (to a lesser degree) are impacting with nock to the right. Please help. Thanks.

[SlowBowinMO]

I think they are so stiff you may be getting "kick" off the shelf/side plate.

[njloco]

Can't be too weak, and your first two arrows look good. I shoot 1535's out of all of my bows, they are from 38# to 54#, with a 50 gr. insert and at least a 100-185 gr. point. Do you notice anything with your arrow flight ?

[Bjorn]

At 15' you are probably still in paradox, and I suspect you are dropping your bow arm/hand so you can watch your arrow?

[Nativestranger]

Originally posted by Braveheart Archery:
I think they are so stiff you may be getting "kick" off the shelf/side plate.

That's interesting. I never thought it can work that way. However the release is pretty quiet. I don't really hear the sound of arrow hitting riser. I will test with a 100 grain tip and see if things improve.

[JRY309]

Carbon arrows recover much quicker then other types of arrows.I bought some used carbons that were about an inch longer then my draw and were showing alittle stiff.So I added more front end weight and they were showing even stiffer.They were in effect bouncing off the riser instead of flexing around it.I tuned the same spine carbon to my bow but they ended up about 2" longer.This was of a longbow cut off center.I feel on bows cut off center carbon arrows tune better if they are longer.I find on my bows cut off center my carbon arrows are about 2-2&1/2" longer then my wood or aluminum that shoot well out of them.

[gringol]

Assyrian bow?  Is that shot off the far side of the bow?

[Nativestranger]

Originally posted by gringol:
Assyrian bow?  Is that shot off the far side of the bow?

I shot the conventional way. Used left hand finger release placing arrow on right side of riser

[Nativestranger]

Originally posted by JRY309:
Carbon arrows recover much quicker then other types of arrows.I bought some used carbons that were about an inch longer then my draw and were showing alittle stiff.So I added more front end weight and they were showing even stiffer.They were in effect bouncing off the riser instead of flexing around it.I tuned the same spine carbon to my bow but they ended up about 2" longer.This was of a longbow cut off center.I feel on bows cut off center carbon arrows tune better if they are longer.I find on my bows cut off center my carbon arrows are about 2-2&1/2" longer then my wood or aluminum that shoot well out of them.

Yes my bow has a primitive grip so its off center and should need a weaker/ longer arrow as you mentioned. However mine are showing weak.

[Nativestranger]

Originally posted by njloco:
Can't be too weak, and your first two arrows look good. I shoot 1535's out of all of my bows, they are from 38# to 54#, with a 50 gr. insert and at least a 100-185 gr. point. Do you notice anything with your arrow flight ?

Yes, the fletched arrows flew ok. I was standing slightly to the right of the target. It's hard for me to see the arrows in flight. I took a video to see if they show anything.

   

[SlowBowinMO]

I can't tell anything about flight from your video but it was a good idea, thanks for posting.

You are shooting with a lot of bow cant, which is fine, but that is also helping to compensate for the overly stiff arrows.

Jumping to 100 grains from 85 won't show you anything, you're tuning carbons which tend to be very point weight tolerant.  I'd slap some 250's 0r 300's on there and see what happens.

[Nativestranger]

Originally posted by Braveheart Archery:
I can't tell anything about flight from your video but it was a good idea, thanks for posting.

You are shooting with a lot of bow cant, which is fine, but that is also helping to compensate for the overly stiff arrows.

Jumping to 100 grains from 85 won't show you anything, you're tuning carbons which tend to be very point weight tolerant.  I'd slap some 250's 0r 300's on there and see what happens.

Thanks I will test again with heavier points and no cant. I think Bjorn may be right the arrows may be still in paradox at 6 yards. I will test the un fletched arrows again at longer distance.

[SlowBowinMO]

Just keep shooting the way you are for now, only change one thing at a time or you'll drive yourself crazy trying to figure it out.  

[Flying Dutchman]

Hi Jimmy,

do you have your Assyrian already? Wow, that is fast! Congrats! How do you like it?

Now for the arrows: you are clearly overspined. The most important factor is that your horsebow isn't cut at all. You shoot it over the hand. If you want to calculate with Stu: measure the bow-width were the arrow comes at the riser, divide that by two and put that number (in inches) in the center-cut option box.

From what I see you are useing GT traditional, 15-35, 29", point weight 85 and a standard nock and insert.

That is even to stiff for my 45lbs@29" Peregrine which is almost centercut!

I would leave the 1535 's at 30 inches and would start with a 125 grains fieldpoint and an insert of 20 grains, so a total front weight of 145. You can order weight adapters in weights of 10, 20 and 50 grains. You need a special GT wrench to bold them in the shaft on the fieldpoint. That system works great! Here you have a link to see what I mean:   http://www.above-timberline.com/gold%20tip%20arrow%20components.htm  You have to scroll to find the components I mentioned.

Hope this helped and tell me about how you like your Assyrian!

[JamesKerr]

I think you are way over spined as well 15' is way to close to be doing bareshaft tuning. Try tuning at 15-20 yards and base your tuning off those results.

[Nativestranger]

Originally posted by Flying Dutchman:
Hi Jimmy,

do you have your Assyrian already? Wow, that is fast! Congrats! How do you like it?

Now for the arrows: you are clearly overspined. The most important factor is that your horsebow isn't cut at all. You shoot it over the hand. If you want to calculate with Stu: measure the bow-width were the arrow comes at the riser, divide that by two and put that number (in inches) in the center-cut option box.

From what I see you are useing GT traditional, 15-35, 29", point weight 85 and a standard nock and insert.

That is even to stiff for my 45lbs@29" Peregrine which is almost centercut!

I would leave the 1535 's at 30 inches and would start with a 125 grains fieldpoint and an insert of 20 grains, so a total front weight of 145. You can order weight adapters in weights of 10, 20 and 50 grains. You need a special GT wrench to bold them in the shaft on the fieldpoint. That system works great! Here you have a link to see what I mean:      http://www.above-timberline.com/gold%20tip%20arrow%20components.htm     You have to scroll to find the components I mentioned.

Hope this helped and tell me about how you like your Assyrian!

Thanks for the tips Ad. I made a mistake of ordering them cut at 29". Will get another dozen uncut ones and tune from there. Though its wierd that i am getting nock right instead of nock left for being overspined. Did you see the video  i posted earlier in this thread? I got the biocomposite version Assyrian and I love it. Fast, quiet and shock free. I think this one of the best horse bow designs. Looks beautiful and primitive at the same time. I don't think you can get more traditional than this.

[Flying Dutchman]

I never lie Jimmy    , The Assyrian bio composite is one of the best out there!
Your nock right makes sense: probably you are so much overspined, that the arrow bounces of the riser, in stead of bending around it. The bouncing will make the position of the nock inpredictable.
But I would prefer woodies with traditional medieval points and nice barred traditional feathers of 4 "at least for that bow though....

[Nativestranger]

Originally posted by Flying Dutchman:
I never lie Jimmy        , The Assyrian bio composite is one of the best out there!
Your nock right makes sense: probably you are so much overspined, that the arrow bounces of the riser, in stead of bending around it. The bouncing will make the position of the nock inpredictable.
But I would prefer woodies with traditional medieval points and nice barred traditional feathers of 4 "at least for that bow though....

I shot quite a bit at the range today and recorded some video footage. It looks like the arrows flew dead straight out from bow like a rockets from a gunship. I am still going experiment with more tuning to get the bare shaft correct.  
I agree on the feathers. I don't know what I was thinking when I selected 3" parabolic.     :(    Now I feel like re-fletching them all with 4" shield barred feathers.

[Flying Dutchman]

I was just jokin about the feathers....

[Nativestranger]

Originally posted by JamesKerr:
I think you are way over spined as well 15' is way to close to be doing bareshaft tuning. Try tuning at 15-20 yards and base your tuning off those results.

Will try bareshaft again at 15 yards. Thanks for the input!