Those bad guys had semi automatic rifles. I believe one had a Ruger Mini 14. Handguns against rifles....who do you think was out-gunned?
I've heard of a cop that shot a bad guy center mast more than one time with a .357 Magnum only to have the guy get a few .22 rounds into the cop before he died. Firearms (even long guns) are not magic wands.
Only disruption to the centeral nervous system i.e. brain or spine, will result in instant incapacitation. Besides, you never know how that magic bullet will perform or fail to perform.
What's a 1938 round?