Joined
·
26 Posts
Hello everyone! i have a 63#@28" longbow and i shoot GT 5575 arrows. My draw is 27". Shelf between +1/4 and +3/8
Arrow Dynamic Spine Required (pounds) would be 50#, according to Stuart calculator.
The 5575 are at full length, 32", with 100 gr. points with an extra 100 gr.
So far, everything looks fine except the FOC is almost 18% and the arrows have a curve trajectory at 30 yards. I would like a flat trajectory, which would increase my accuracy at different distances.
I started to play with Stu's calculator and found that the ideal arrow for my bow would be a GT1535 (!!!) with 100 gr. point, extra 70 gr. for the point and an extra 50 gr. for the nock. The dynamic spine would be the same as the 5575, but the FOC would be near ideal, 10.7%. The "perfect" arrow for this bow is extremely different from what the factory suggests....(http://www.goldtip.com/selection.htm)
My question is: how can it be that arrow builders tables show such useless values and why did we have to wait so many years to have some smart guy to understand that dynamic spine was everything ? i still cannot understand....
- chris
Arrow Dynamic Spine Required (pounds) would be 50#, according to Stuart calculator.
The 5575 are at full length, 32", with 100 gr. points with an extra 100 gr.

So far, everything looks fine except the FOC is almost 18% and the arrows have a curve trajectory at 30 yards. I would like a flat trajectory, which would increase my accuracy at different distances.
I started to play with Stu's calculator and found that the ideal arrow for my bow would be a GT1535 (!!!) with 100 gr. point, extra 70 gr. for the point and an extra 50 gr. for the nock. The dynamic spine would be the same as the 5575, but the FOC would be near ideal, 10.7%. The "perfect" arrow for this bow is extremely different from what the factory suggests....(http://www.goldtip.com/selection.htm)

My question is: how can it be that arrow builders tables show such useless values and why did we have to wait so many years to have some smart guy to understand that dynamic spine was everything ? i still cannot understand....
- chris