Can we see your research that supports this claim.
http://www.firearmstactical.com/hwfe.htm
http://m4carbine.net/showthread.php?t=19887
Along with these, I rely on my experience. I have spent two tours in Iraq as an US Army infantryman (invasion of 2003 and 2005). Since leaving the Army I have worked as a patrol officer in one of the largest cities in the US.
In my experience all of the service calibers work if you strike a vital organ(s) and dont work if you dont.
My friend has been in 2 shooting on duty. Both times he shot the bad guy at close range multiple times with 230 grn Federal HSTs. Both shooting had several torso hits as well as head shots. Both suspects survived.
Was at a police involved shooting a while back where a guy pulled a gun on an officer. The officer was on the ground and the suspect was on the second floor walkway of an apartment complex. Officers round (230grn HST) hits the suspect in the lower chest/upper stomach area under his arm. Bullet completely passes through his torso and exits near his other shoulder. The suspect ran through the complex and took 3 officers to physically fight him to get him into custody. They then walked him to the ambulance (They will RARELY come directly to an active scene) where he was rushed to the ER. He barely lived.
My training officer shot a guy who was robbing people inside a shopping mall with a Mac 11. Round (again a 230grn HST) entered the side of the chest and through the heart. Bad guy was DRT.
Had a drug dealer shoot another drug dealer. Rounds were Remington Golden Saber .45 (unknown weight). One shot destroys his elbow. Second shot hits him in the temple from a front facing shot. Bullet deflects down and out the cheek. Enters the chest near the collar bone. deflects off a rib and ends up on the other side of his torso near hi pelvic bone. He was still conscious enough to tell us who shot him.
In Iraq in 2005 I witnessed an Iraqi police officer shoot a man laying an IED with a Glock 19 using Nato ball ammo. Round enters the SOB in the side of his chest and the guy, who was running in a full sprint, faceplanted and never even twitched.
Had a homicide a while back where a guy shot his roomate two or three times in the chest with a 9mm and he was DRT.
Like I said earlier, handguns wound by destroying tissue that the bullet passes through. They do not have enough velocity to do significant damage outside of the wound track. 2/10s of an inch is not a significant size difference. Modern defensive ammunition all expand well and penetrate well. Look at the gel shots from the post above. None are significantly "better" than the others.
Our training personel have shown us that departments that issue 9mm exclusively have no complaints when using modern ammunition. NYPD has been using the 124 grn +P Golddot for several years now and I have heard no complaints.
BTW I carry a .40 S&W and am soon switching to a .45 because I dont care for the recoil characteristics of the .40. If I could carry a 9mm I would have no problems with it.