I' m shooting 340' s with 3 7/8" vanes and 100 grain points. The shaft is 27" due to my overdraw. I' ve never bothered to check my FOC becuase I don' t believe in it too much. My bow paper tuned well, and from there I zeroed everything else in. I don' t have any erratic arrow flight and they stack right in there. Although, using the MZE may be helping...