MUZZYMAN88, Even though an arrow can check very semetrical on a spine tester. In most cases there is one spot on that arrow that preforms the best. Nock tuning is the best way that I know of to find that spot. I shoot with(but cant compete with) guys that shoot 300 with 50+ Xs and during a shoot I see them rotating a nock just because the arrow isnt hitting the X in the middle of the X ring. Must be terrible to shoot like that ha ha. GGBH