Ditto on 5 Shots advice.
You also can sometimes experience apoor arrow flight if your shooting form is flawed.
I also like to # the vanes on my arrows according to which ones spin and fly the truest.
I have had arrow flight with the muzzy 4 blade 100 grain practice heads that matches my arrow flight with the heads with the hunting blades.
With MUZZY BROADHEADS its all been good for me