A:
The 5/16 adapter will not seat properly in the ferrule and it will be more difficult for the broadhead to spin true. I recommend the long 11/32 adapter for the best fit. A little may stick out the bottom of the ferrule on the broadhead, but that will not make a difference as far as penetration or performance.
Answered on 7/17/2012 by Justin from 3Rivers Archery