Originally Posted by OKbowhunter
I am trying to gain more speed for a youth/ladies bow. The bow is shooting on average about 185 fps. My question is, with arrow weight only , what is the average reduction in grains to gain 1 fps? Is it, (-5 grns = +1 fps)? I think I have read this somewhere before but for the likes of me I can't find the info.
You are pretty much right with the 5 gr. formula. I would be careful not get the arrow weight below 6-7 grains per pound of draw weight. It is said that going lighter really fatigues the equipment. Such as, a 40# draw weight bow needs at least a 240 gr. arrow.
If the rig is for target shooting, you may be able to flatten it out with lighter arrows. If the rig is for hunting, heavier arrows will dig in deeper.
Hope that helps.