On the Bear Razorhead, the factory used epoxy to install the inserts and it is not uncommon for these to be mounted crooked. You'll need to heat the head up (I use a propane torch) until the epoxy softens enough to remove the insert from the ferrule. This is a stinky job!
Also, it is not uncommon for the indentions in the ferrule for the bleeder blade (at the back of the head) to be inset a little too deep. When this is the case, it is nearly impossible to get an insert glued in properly so that the arrow will spin true.
I bought a ream (5° taper) and only have to make a few turns in the ferrule, by hand, in order to knock the high spots off of the indentions.
After a "dry run" to make sure the head spins true, I then use hot melt glue to install the insert permanently.
Once straight, I have never had any flight problems (no matter the blade alignment, horizontal, vertical or even caddy whompus).