My experience has been that Slick Tricks are easier to get field point matchining flight and impact than Muzzys. Still though, I have not found Muzzys to be a really big problem. If the Muzzys were used, and had been shot several times, there is a chance that the ferrules are bent. The ferrules are a somewhat weak point with Muzzys, IMHO. The aluminum ferrule can and does bend. The blade interlocking system is the strong point of those heads I suspect the Muzzy broadheads that you have are not spinning true to the arrow shaft.