I am not really disagreeing with you per se, but shot placement is key. Big bullets come at the expense of capacity, which is equally as important as stopping power and shot placement.

The best advice I can give to a new CCW is buy a combat grade 9mm (Glock, M&P, HK, Steyr, etc.) and SHOOT SHOOT SHOOT! buy ammo buy the 1k round box, run some training classes, and get to know your gun the best you can. Big bullets don't help when you can't control them or they run out.

Remember, at the end of the day, handgun bullets poke holes in people, but rifles blow things up. There's no magic round that will stop a person 100% of the time in one shot in handgun calibers, so training and shot placement can be what seperates surviving and going TU.