Helical helps stabilize but is not necessary. Especially if you have a rest that won't accommodate a helical fletch. If the field points are grouping together and the slick tricks are grouping together at a different point of impact, its a tuning issue. Easton's Tuning Guide should help. There's a great graphic that tells you what adjustments should be made depending on where the BH's are hitting in relation to the field points. Also, there's a sticky on that "other forum" (caugh, AT) in the hunting section where a guy described how he brought his field tips and BH's together step by step.