Sounds like your arrow spine is off or they are not aligned with the shaft very well. I have used the older Muzzy 90 gr 4 blade heads for the last 15 years and have always got them to shoot without much fuss.
I really like those and watch for them on ebay. They go right through deer, elk and sometimes bear. Mostly, stuff dies within 20-50 yds. Best broadhead made imho.
