ok, at risk of sounding stupid, im trying to rebuild my FAL L1A1 into a highly to moderatly accurate rifle. the problem im having is i cant figure out what kind of parts to put on it. its an Imbel lower receiver which im pretty sure is metric and and the upper is metric as well... i think. but from my research, it looks as though the gas block is inch. so what is the deal. is this possible to mix and match? the gun, as it stands now, pretty much operates flawlessly so can anybody help me out with this one?