If you have a Hornady Lock-n-Load AP, you have undoubtedly broken the primer drive rod bracket. Hornady customer service will send you a new one for free, but it's still a PITA. I found an aftermarket bracket on Amazon that claims to solve the issue. When the primer plunger sticks, now instead of the rod popping out of the bottom only and then breaking the bracket, it will now also pop out of the bracket. It is a simple matter to snap the rod back in without loosening any screws and you are back in business. I have tested it with a "manufactured jam" and it worked as advertised.
This breaking of brackets was my only complaint with the press, and now with this in place I can say I am 100% happy with my Hornady press.