Re: AR-15 question
get a copy of the bushmaster catalog, they have a drawing showing the actual differences between full auto parts and semi auto parts. this is important ! if you buy m-16 parts and not realize the difference, install them in an ar 15 you have created a class three weapon even though the gun will not function fully auto at that point. you say your buddy has a full auto version. take a moment and compare the difference of the external lower receiver to yours and you should also see a difference or two.