Did you resize it Bullseye?
also, I SAW YOU! hah hah. I remember seeing you at Skirmish last year, I was lugging the bow-gun around.
If you don't have the plunger-size set right for your reach, it can 'knock' against the end of the tube, and fire that piece right off. I did it once with a used one, before I rebought a new arrow and cut it to right size.