In my days with the USMC I was taught that 5 drops of oil was all it needed.
1 drop on end of barrel
1 drop on barrel locking lugs and hood
1 drop on disconnector rail
1 drop on each frame rail
Assemble and wipe down with a very lightly oiled rag. Really don`t know if it`s right or not, but I`ve been doing it this way since 1957, works for me...