I would not continue to remove any material, especially from the trigger lever, on the other hand, a little polishing won't hurt, but most likely won't cure it either? An assembly check I use primarily, is to assemble the frame assembly with the sideplate, less the upper receiver. I then, first, make sure the sideplate is both straight and square, and at the same time, tight to the frame as well? Then I squeeze the trigger all the way and see if the top/front, edge of the trigger lever is in line or paralell with the front / inside, edge of the side plate. If it is perfectly in line, that's all it can do, and we need to re-address the sear bar. A similar check is used for that. When you have the barreled receiver assembly off of the frame, check to see if the front outer edge of the sear bar, (the little plunger end) is even with the protective shelf just above it? If not, an adjustment is needed. I suspend the two ends of the sear bar across two blocks or high density plastic, and using another piece of plasitc, I tap the sear bar right at the relief / notch, for the pivot point of the sear bar! I generally start by bending the end of the sear bar IN towards the receiver, making it flush with the outer shelf edge, at rest, with the above mentioned referance shelf? too much? flip it over and go the other way, too little, flip it again. A few thousands will make a big difference. Go slow, tap lightly... best, til....lat'r....GT....
BTW, on the frame assembly, when doing the test for the trigger lever going out far enough, you can also check the lever return in the sideplate when the trigger is returned? It should go all the way back into the side plate to allow the disconnector to operate properly.Making adjustments in this area to the trigger lever require some additional skill sets that are not for the faint of heart! Annealing, re-forming, heat treating,and re-tempering of the trigger lever is what would be required?..
