If I had a group of newbies with minimal training and loads of available ammo, I train them to only fire a M16 in auto when you know the bad guy was 10 feet or less. Otherwise 3 shot select for suppression fire. Would also select if in jungle or occluded fire zones.
If I had a group who had enough experience to actually aim, M14 all the way. The heavier load gives the experienced more confidence and that reflects in better results. There is a lot of psychology built into expectations and the Garand and its children have it in spades.
FYI: The M1 Carbine is not what we are talking about here, totally different weapon!
I love my little .30 caliber M1 carbine - fun as hell knocking over bowling pins on the range.