Tfox, spine of the arrow was fine for both bows. One was just a faster bow. Granted they are two different bows with different amounts of stored energy, but the fact remains that it is the same weight arrow at two different velocities and trajectories were way different. Both bows were tuned and had great arrow flight. The amount of stored energy is irrelevent, the fact that it was two different bows shouldnt much matter either. All else being equal the two major contibuters to trajectory are speed and weight. With a 20fps loss in speed itmade a heck of a difference in trajectory for that arrow. So if I were shooting the same bow, wouldnt a loss in 20fps of arrow speed be a comparable loss in trajectory or possibly more because of the increased arrow weight to do so.