dont forget momentum into the factor......

i'll take a heavier arrow moving slower than a faster, lighter arrow every day for hunting. it will carry its energy better

momentum=MASS+VELOCITY

a 350gr arrow doing 305 fps has a momentum of 106750 and a KE of 72.31

a 450gr arrow doing 260 fps has a momentum of 117000 and a KE of 67.56

thats roughly my bow for IBO setup vs what i really shoot....i loose some speed..and loose a few pounds of KE, but i gain a good bit of momentum...it will be harder to stop my arrow vs the lighter, faster IBO arrow.

i played with numbers for a while to find the point where i have the fastest arrow producing the most KE...then found arrows that fit the bill. (i like math and numbers) i found that any heavier just takes away speed but doesnt do much for KE...i found it to be a nice arrow weight for my setup...though heavier will add more momentum...

my point is KE isnt everything...though were talking deer that weigh less than 300lbs and if shot in the vitals, dont really have anything that is tough....hide, muscle and maybe ribs, which break and bend fairly easy...