Kinetic energy does not wound. Temporary cavity does not wound. The much discussed "shock" of bullet impact is a fable and "knock down" power is a myth. The critical element is penetration. The bullet must pass through the large, blood bearing organs and be of sufficient diameter to promote rapid bleeding. Penetration less than 12 inches is too little, and, in the words of two of the participants in the 1987 Wound Ballistics Workshop, "too little penetration will get you killed."" (emphasis added)
-- Handgun Wounding Factors and Effectiveness
by Special Agent UREY W. PATRICK
FIREARMS TRAINING UNIT
July 14, 1989
I know this is the prevailing wisdom these days, but I don't buy into it 100%. Think about it. This logic is based on the subject bleeding out. That does not happen quick enough to physically stop someone close to you with a deadly weapon. They dismiss "shock" too easily. I know its not been physically
proven that shock matters, but something
accounts for all the quick one shot stops that don't hit the vitals. I believe the feeling or in other words the psychological impact of being hit with a high energy projectile may easily have something to do with it. Just what was it that made the 125gr .357 magnum the legendary manstopper that it was? That round is clearly in the light/fast camp. I'm carrying 155gr when I carry my G20. Or maybe I'll get a 9x25 Dillon barrel for it.
Edit: Just noticed I essentially reposted what VCreed already said.