Re: nock problems
I have never had the issue you are having with CX knocks, been shooting them for years with different makes of strings. The only time they have broke is when hit by another arrow.
Its really weird that you have snapped every knock, not saying that a bad batch does not occur, but everyone and even replacement are snapping. I would have to say that there is something else occurring other than just the knocks. As noted, are the knocks fully seated against the bull color. CX have the bull collar and the knock should be solidly seated.
Did anything else change along with changing arrows? I would not expect the serving to be that thick that it is snapping them. Do you have a string loop or one of those metal loops?
RIP Tuff 98-11, So many hunts, so many good times!