gentlemen, im having a problem with my m14. first of when i first got this norinco m14s i immediately took it apart and swapped out parts with some usgi i had laying around. my current setup is as follows....usgi unitized gas cylinder with sadlak piston, trw bolt, trw trigger group, nm spring guide and wolf op rod spring w/ buffer, some other things as well but i dont think they will pertain to my current problem. the rifle is completely extracting spent brass and failing to chamber new round from magazine. i have 6 different mags both norinco and usgi and the problem persists. gas port hole lines up from barrel to gas cylinder, there is no junk in the gas port hole, and gun is well lubed where it should be. any help on this issue would be greatly appreciated.