My coworker and I went shooting a few weeks back and his CZ75B was having some problems. When engaged in slower fire, and taking up the rearward travel of the trigger, the trigger would not fire the pistol and just be frozen and not able to travel any further back. I encouraged him to send it to CZ for service but I'm curious what might be causing this problem. He says he hasn't been able to replicate the problem at home dry firing with an empty mag in or out.