“Trying to stop a bad-guy with a nine mm is like trying to stop a charging buffalo with a twenty-two. Might as well use a fly-swatter”.
Such statements were common when I was a kid, and at the time there was some truth to them. Many experienced shooters, veterans, and L.E. officers still preferred the hard-hitting .45 ACP, (Automatic Colt Pistol) to the 9mm with its smaller, lighter and more streamlined projectile.