Hey Daniel, nice pistol! I like how burly it is, I usually make my mini crossbows too light and get a lot of hand shock when I fire them. Regarding the issue with your prods breaking, I'm wondering a couple things- I don't see a photo where the prod is strung to see how much down-force there is on the string. Not that the pressure of the string on the bolt track would increase stress on the prod, probably the opposite, but since the fiberglass lathe you've been using is straight, it would need to be angled quite a bit to provide adequate clearance, and maybe there's to much twisting action when fired for the fiberglass to take. The other thing is the weight of the bolts you're using. Maybe they are too light for the draw of your prods? I've learned that heavy projectiles are much safer when working the kinks out of a new design. Too light and it's just as bad as dry-firing.