I bought a police trade in smith and wesson 4006 with six used magazines 11 rounders. I have changed recoil spring and magazine springs oem. The problem I am having is that the last round fails to go into battery (failure to feed) can someone here help me on this matter is it the follower the feed lips wonder what is wrong does it with all the mags the followers are kind of worn. I polished carefully to make them smooth as carefully as possible. Havent tried them out yet since the polishing too much rain right now in south texas to go out and shoot please help