I have been playing with some muzzy 115grn four blade broad heads. they group right with my feild points 100grn with very little adjustment. Now that I have them both hitting the same spot the field points are still grouping good (5arrows 21/2in circle at 20 yrd) but they are fishtailing slightly, should I just leave well enough alone, or is a sign of some tuning issue that I'm just not seeing?