To eliminate variables i would completely remove the Trigger pretravel set screw. The pretravel set screw is located in the top of the Trigger and is accessible through the top of the Trigger with the pistol slide removed. Once removed, i would test the pistol without the screw installed. For clarity, i am not talking about the Trigger overtravel set screw that is located in the face of the Trigger but the other pretravel set screw located higher up in the Trigger.