All service caliber handguns (9mm through .45 ACP) suck at stopping threats pretty much equally. Knockdown power and stopping power are myths when it comes to handgun terminal ballistics. All modern JHP ammo in those service calibers sucks about equally, and all FMJ ammo sucks even more.
If you want a guaranteed one shot stop, I suggest hitting your attacker with a Chevy Impala going 85 MPH. That would have a 3,500,000 Power Factor, which definitely makes major.