A:
The shank can vary but of the 6-pack that I measured with a mic was a range of .130"-.145".
They are not perfectly round either, so I would not pre-drill the arrows before getting these. It will require you work with each shaft, and I recommend using some glue/epoxy.
Answered on 10/4/2010 by Johnathan Karch from 3Rivers Archery
