Define "effect"...
I've been attacked twice in my adult life, far more times than that in my youth. Both times as an adult were right up in my face. All the armchair commando gun training in the world would have been useless from chest to chest. Both times, had I been carrying a firearm and decided to use it, it would have been stuck in their gut and fired from point blank range. There was no time for "shot placement", no time for a proper draw and aim...they were literally up in my face chest to chest. You can practice all the "push-off, draw-fire double tap body, single shot face" stuff all you like...try it when a ticked off thug is in your face and tell me how well it works for you.
I don't care about killing someone, I care about getting them off of me. If they die in the process, so be it. If they back off, mission accomplished. Your definition of "effect" is far different than mine. "Effect" to me is what a person will do when shot at point blank range and as I stated before, that is 100% up to the individual.
Am I saying that a belly shot with a 22 magnum snubbie is a great solution? No way...but all of this silliness about 7 yard draw and fire, shot placement, and other silliness is often made by people that have never been in a street fight.