Bow performance gurus

[rybohunter]

OK I don"™t know if this can be figured out, but if it can, I know someone here will be able to do it.

Say I take my bow, drawing #70, shooting a 456 grain arrow 267 fps. Actual measurements.

Now if I take the same bow, turn it down to #62, & shoot a 340 gr arrow. Can anyone estimate/predict my speed?

[Sylvan]

If I assume a virtual mass of 125 grains for the first condition, I calculate 280.9 ft/sec for the second condition.

[JoshKeller]

just doing the math quickly, i came up with 283 thats usually accurate to within 5 fps or so.