I didn't want to hi-jack Burch's thread, but I'm sure confused. I used Stu Miller's dynamic spine chart and here's what I came up with:
My bow, 50# @ 28 (weighed). I draw 28.5", so it says I'm drawing 51.6#s at most.
I shot 2117s, 30.5", with 170gr Zwickeys, 26gr inserts and 20gr additional weight behind the insert. 3-fletched, 5" feathers. Seemed to shoot OK, and I killed a deer with the setup last fall (roughly 12 yd shot. I was fat, dumb and happy until I stripped the feathers off my worst looking arrow and shot it. Flew like a piece of cooked spagetti, hit 10" right from the group, almost sideways, nock left.
Cut the bare shaft back to 30.25, removed all internal weights and cut the point weight back to 145 gr. The bare shaft flies like it's on a wire and hits straight on in the group.
Do I have some kind of horrible release that requires a stiffer arrrow, or do I just not understand Stu's chart.
For what it's worth, I bought a 48# R/D Lost Creek longbow and it only likes arrows spined at 80# by Stu's chart. Went up to the trad archery shop and we wound up going WAY up the ladder on spine weight - 2219s with 145 points, 30.5 length and it shoots bullets.
Waaahhhh?
Ron