3 blade 100 grain muzzys have always been one of the more difficult heads for me to get good flight with . 5shots site will give you a good starting place , along with eastons tuning guide , that you download from their website . A petpeeve of mine is to have enough fletching on your arrow , 5" feathers will give you enough steering to counteract the muzzys steering in the front of you arrow . Len says there are 3 things to tune for good arrow flight , and he is dead on . The archer , the arrow , and the bow . When one is out of whack it will screw up your arrow flight / consistency . When my arrows are tuned so that a muzzy will hit with my field tipped arrows , I have found that any 100 grain head I put up front hits with them .