M77man

I have an 08 Diamond Black Ice and the birth cert states 298 fps with a 350 grain arrow at 70# and 29 inch dl.

My arrows should be in the neighborhood of 365 grains at 65# and a 28 inch dl.

How fast should it be shooting then? I'm going to get it through a chrono eventually but it would be nice to anticipate probably what it will be shooting.

Thanks

Bols

Others might have a better guess, I am saying around 270-275 fps. I know for sure, you are going to loose approximately 10 fps just on the 1inch difference in drawlength.

sluedtke

For every inch of draw length you go down you will lose 10 FPS

For every 5# draw weight you go down you will lose 10 FPS

For every 3 grains of weight your arrow is over IBO you will lose 1 FPS

For every 3 grains of weight you add to your string you will lose 1 FPS.

So I would guess about 273 on the head. It could shoot a little slower it seems like they always do.

M77man

Thank you for the info, we'll go with that. Not like it really matters for a hunting bow on out to no more then 40 yards right? But just wanted to know.

sluedtke

A heavier arrow helps out in down range shots like 30 yards and more because of kinetic energy, but it will be slower because of the weight.

buckmaster

heres a pretty neat little calculator.

http://www.thearcheryhut.com/calculators.php

sluedtke

LOL i just gave that calculator to somebody else on another thread... thats what I used for this info too.. found out the fps calc is a little bit off so rely on the words on the left and your own calculator for the fps...