I shoot 4 blade Muzzy 100 gr. and they fly just like my field tips, but my bow is tuned perfectly. According to the Easton Tuning Manual, if your broadheads are hitting below your field tips you need to lower your nocking point, or you can just raise your rest. Do this in 1/16" increments until your broadhead and field tip groups come together and are impacting in the same place.