I entered the PCC game with a PSA complete lower and upper. Slapped on a red dot (holosun), and ran it! It liked to dent bullet noses until I polished the sharp transition from ramp to chamber. Now it runs like a champ.
Now its time to play with the recoil impulse. Since I don't reload, and I like shooting cheap 115s, I'm about to put a JP 308 buffer spring in it. Then I'll test some nylon spacers I made for short-stroking it. The trigger is pretty heavy, so JP 3.5 springs are on the list.