In 20 plus years of making woodies I find that most bows are more sensative to spine than weight. Just want to hear some feedback from others......Shoot woodies that are spine 4 to 5 pounds apart or 25 grains apart with same spine?
I have been making wood, alum, glass, and carbon arrows for over 40 years. I now only shoot wood arrows. I have not noted any relationship of arrow flight to weight within reasonable limits, other than speed and the fact that the center weight must be forward of center. Thus, spine I see as the major factor when viewing arrow flight. There are several factors that must be considered when selecting spine for any given bow.
I hope that I understood your question correctly.
Correct Spine = Correct Arrow Flight
(- + Weight) = (+ - Arrow Speed)
Did I get this right ?
I have shot wooden arrows up to 80 grains difference in weight out to 20 yds and not noticed a great difference in flight other than alittle less speed maybe, but I have never verified the speed with a chronograph. Beyond 20 or 25, the heavier arrows drop much quicker. Spine is a different story however. With my longbows I can only go about 8 lbs spine difference before I start to notice a stiff or weak arrow. My recurves don't seem to be as sensitive to spine, I can shoot maybe 20 lb span in spine. I remember when I got my first longbow, I almost gave up completely with it because it was so sensitive to spine compared to my recurves. I will take close spine over weight everytime.
Shooting arrows of different spines will change your horizintal dispersion. Different weights will change your vertical dispersion. 5# of spine is a 10% change in a typical bow. 50 grains is a 10% difference for a 500 gr arrow. We're usually within 20 grains even with wood arrows.
Personally, I do think weight is pretty flexible
Weight does not show up very much inside 20 yds. An 80 gn difference makes a 1-2 in drop for me and my brain makes the adjustment. Whether or not a small variance in spine shows up has a lot to do with side cut. On self bows a few # of spine will throw flight off. A bow that is cut 3/16 past center will tolerate 10-15# difference in spine. At least this is my experience.
Spine is critical, weight is not. I try to keep weights within 30 grains or so.