I have a pair of Lauer lowers that have a small variation in the thickness of the right wall in the fire control parts area (pics below). The folks on calguns said I should not worry about this; any AR experts here want to respond? I looked at a machining drawing for the AR-15 receiver, and I could not find dimensions listed for this wall. Is it true that this is not tightly specified? The difference in width is about 1/32 " and accounts for an 11 g difference in mass between the two lowers.
(note the difference in relief around the takedown pin area)
(note the difference in relief around the takedown pin area)