I have a brand new taurus TCP that when i squeeze the trigger it will not fully depress and drop the hammer. With the slide off looking down from the top there appears to be a plastic ball bearing with a pin in the middle. The pin appears to be loose which is causing the bearing not to roll forward. Any ideas as to what this ball looking thing is called? I was able to push the pin in the middle back down and the trigger would then fully cycle, but the pin worked its way out (up) again = no joy. please help if you know what this ball is called.