This is the relation of the striker (top) and the sear (bottom) as they sit while the XD is cocked (but unlike the picture the two parts will be touching and under pressure). The firing pin wants to fly forward in the direction of the blue arrow but is held by the sear. The total contact of the sear and the striker is the same as the wedge shape in front of the blue arrow. There in a pin that holds the sear into place(the hole in the sear) when the trigger is pulled the trigger bar moves the striker saftey lever (not shown but would be next to the sear) a nub on the lever contacts the nub on the sear and moves in the direction of the red arrow. The sear rotates around the pin (where the hole is) so the back of the sear moves down and out of the way fo the firing pin which when released slides over the sear. The contact that you would feel in the trigger is that area where the small wedge is on the striker. By putting some grease on this area where the contact is will help no matter what you do. Then if you feel the need you can use something like flitz polish or jewlers polish and polish the face of the sear and striker where the contact is. To find out where the contact is use a permanant marker and mark the faces then put the slide on the frame pull the trigger then pull the slide back and pull the trigger again. Do this about 5-10 times. Take the slide off and see where the marker was rubbed off use the rubbed off area as a guide where you need to polish. A warning though you are smoothing out the metal not removing metal for no reason do not round off the edges or remove metal. As I said if you are not comfortable doing this use grease and you will get the same temporary effect.