Had another aha moment and thought I would share.  Shooting my field tips over the summer I have managed to get fairly consistent groups.  Just put together some broadheads with identical shafts, feathers, nocks, and feathers.  However, I was getting some strange flight every so often.  I took a file to the nocks to loosened them up a bit and bingo. Broadhead is now the same as field tip.

Makes me think that my nocks were tight on the field tips earlier in the summer and have gotten worn loose by shooting so often. Anyway, just thought I'd share in case anyone else is getting some wild ones when converting to broadheads.
Josh

another trick that I use is to dip the knock into hot/boiling water and then push onto the string.  Gives a custom fit and not sanding.

Bob Urban

Two methods I should try.  Generally, I just use my teeth.

I actually prefer fairly snug/almost tight nocks.

I guess that the heavy arrows and high poundage I shoot allow me to do that without affecting arrow flight.

Teeth works for me too

QuoteOriginally posted by TxAg:
Two methods I should try.  Generally, I just use my teeth.

What are you doing with your teeth?
Using them to pry the nock apart?