weight vs spine
 

what i'm really wanting to know is what is the difference between the two when it comes to arrows?
what brought this question up was my previous post about my set up.

RE: weight vs spine
 

I really dont care for the GPI or grains per inch of an arrow I am more interested in the spine of an arrow.

You can get some high GPI arrows that are weak on spine and people think because their arrow weighs x amount it is good to shoot then wonder why they have so much trouble tuning their bows.

Pick a spine that is suited for your bow and go from there or you can be like me pick a head weight then design the arrow around the head:D

RE: weight vs spine
 

from what ive gathered by looking at the #'s at least on aluminum arrows..

is that outside diameter of the shaft has more effect on stiffening the spine than the wall thickness...

for example
a 2216 shaft has a spine of .376 weight is 348 grns
a 2018 shaft has a spine of .474 weight is 357 grns
a 2020 shaft has a spine of .426 weight is 392 grns

target shooters will shoot arrows like a 2413 because its a fatter shaft it is a stiff shaft spine .365 and its fairly light because of the thinnerwall thickness wieghing 302 grns plus they cheat the lines with there big arrows.

wall thickness (the last 2 #'s) have more effect on keeping the weight of the shaft up. but it stiffens at the same time just not as much as the diameter

RE: weight vs spine
 

Apples and Oranges. As Aussie said; start with your intended head weight. Then choose the proper spine (stiffness) from the charts - based on the draw weight of your bow (you should measure this), the cam type, and the arrow length you intend to shoot. The actual weight of the finished arrow is only a function of the gpi of the particular shaft you chose. There are very light arrows with a .300 spine (very stiff), and very heavy arrows with a .500 spine (pretty soft). The weight issue ismostly a matter of balancing out trajectory vs. penetration - although some of the very slim shafts now offered can deliver both.

RE: weight vs spine
 

great guys now i gotta get new arrows because my spine is too soft (2117's @ 31") although a heavy arrow with the 115 gr. BH.thinking about going with the st epic now. was thinking about the a/c/c's 3-71 but i can lose 106 grains with the epic.

RE: weight vs spine
 

The A/C/C's as well as the Axis FMJ are great hunting arrows. Not cheap, though.