Clemenza wasn’t teaching Michael to shoot. He was teaching him what do do and what to expect in the restaurant. Part of that would be hearing an unsilenced .38 indoors (not the same as usmc outdoor rand practice with a 1911). Indoor shooting noise can be painful. But usually the shooter in a life or death situation hears nothing. Not until much later when one notices that one’s ears are ringing.
Right on.
Mikey was a Marine and a decorated hero.
But he probably didn’t shoot too many Kraut officers in the face over a plate of pasta.