My PT 745 PRO pistol has not been firing reliably. The firing pin strike seems week and the firing pin dent in the primer is off center. Have anyone of you tried to fix this problem your selves? There might be some crud slowing the striker or it might worker better with a stronger striker spring. What is the best way to disassemble the slide? How is the plastic plug in the rear of the slide removed? Does the rear sight have to be removed? The set screw on the rear sight is extreamly tight. Is this typical?