Put a Sidewinder(have used them for 5 seasons) on my new arrows(this spring)that have Quick Spin vanes, shot to the left 2 inches. Put it on my old arrows with 4 inch vanes, dead on. The arrows are the same GT XT Hunter, with 2 exceptions my new ones are an inch longer and the mentioned Quick Spins. What do you think? I will more than likely be hunting with my old arrows this Sunday, but what could make them fly different? The Quick Spin or arrow length? I shot at different yardages, tried different arrows but they fly to the left while on the new arrows.Thanks.