When I went into the Army the M16 didn't have that little bump to keep the brass from coming straight back into your collar. ]
the Canadian version as originally issued has the casing deflector, so I shot left handed. for whatever reason, it drove the intructors nut`s when recruits did the drills on the weapon left handed, as the rifle was new to the Canadian army when I joined. no consideration had been given to developing left handed drills, and 30 years later, I`m not sure if that has changed
I`m right handed but shoot left. I shoot either way pretty much equally.