My question is Exactly what can a certified Glock gunsmith do to improve the trigger pull that I cannot do myself? I am not saying this to be smug or a smart alec but I am trying to get my trigger to the smoothest point possible. I have already polished the stock trigger bar and installed a Glock 3.5 connector. However, it still seems to me that there is something "grating" during the trigger pull. Is this due to plastic "burrs", out of tolerance frame or what? Can a Glock gunsmith, for example, enlarge the trigger port if in fact the trigger is rubbing on the frame? Just curious.