Steve- thanks. I know this only from a bullet fired from a gun. I was looking for some variable, but when you put it that bluntly scientific the only variables are bad arrow, wrong release. Badger- The arrows were 26". I was probably overdrawing the bow at the last second. Shooting a 550 grain arrow at 60+? pounds. and underdrawing at 30 yards. The shots were 175, 152,177, 180, 148, and 180.7. Keep in mind the bow had 10" of reflex. and a non bending still reflexed handle at full draw. I was expecting 150-155fps. I didn't measure the curve till after shooting it. 28# @ 10" and 38@ 15. Goes to show unless you have a mechanical hold and release a chrono is not a good test.