I never saw an individual 'cock' a shotgun with their off hand before Terminator 2. Now I see it being done in history documentaries...is this a correct action? I never saw an individual 'cock' a shotgun with their off hand, while letting their firing arm hang loose  before Terminator 2. Now I see it being done in history documentaries...is this a correct or are directors trying to make reloading 'macho'?

By cocking I mean as a right hander, letting go of the shotgun with the right hand, allowing the stock  to swing down so the barrel points up, then moving the left hand, still gripping the handgrip, in a sudden down then upward motion to chamber the next shell.