way back in the early 80s when I shot the Soldier of Fortune match there was a Springfield Armory gunsmith working on rifles. One guy kept asking questions. He had oiled his M1A and it did not function well. The gunsmith said " you grease an M1 and M1A".
The guy said "yeah, I keep hearing that". The gunsmith said "well, are you finally getting it?".
He went on to say, 'you grease the M1/M1A action, you oil the M16/AR15. Don't confuse the two'. I have ever since not confused the two. Not that I ever did.