ORIGINAL: Roskoe
Here's an arrow mass mystery: my Vectrix XL shoots an otherwise identical Axis ST and an Axis FMJ withing 2 fps of each other. Checked it on another chronograph. The FMJ weights about 30 grains more than the regular Axis ST. Should be about 10 fps slower. Other arrows are about where they should be - a 350 grain arrow is going a little more than 20 fps faster, and a 500 grain arrow is going almost 20 fps slower.Not sure why, but I'll take it
I really think we would find that each cam design, bow weight, draw length combo has a particular weight arrow at which effeciency peaks or is at it's best, and could give us some skewed numbers we are not used to.
Usually more weight equals more KE, but those numbers with modern Bow design are slight. A sweet spot in arrow weight and Voila numbers we are not used to.
My thoughts are that even arrow material could play a part in energy absorbed from the Bow?? My 400 grain arrows are the new Aramid Kevlar shafts.
I doubt any contact is the issue on my setup with feathers and a Limb Driver.
340 grain arrow less KE
400 grain best KE
500 grain arrow slightly less KE
I sure would not give up the speed differencethere is between a 400 and a 500 grain arrow for even a slight gain in KE and I actually lost a tad
Numbers from My Guardian 60# 28" draw
326 grain arrow 280 fps 56.77# KE
500 grain arrow 232 fps 59.77# KE
Difference of 3# KE
Numbers from my General 60# 28" draw
326 grain arrow 278 fps 55.96# KE
500 grain arrow 228 fps 57.73# KE
Difference of only 1.77# KE
On the Guardian and General I never shot the 400 grain arrow. Maybe I should!!
Dan