Hi, Tom:
FWIW, I was a Technical Consultant with IWBA, also personally vetted by Fackler. He invited me to test ammunition in his lab at The Presidio in the early 1990s.
During a traffic stop recorded on dashcam video (and can be seen on
YouTube), SC Trooper Mark Coates, a former Marine, was shot with a .22 Mini-revolver. The bullet entered his chest through the armhole of his vest and cut a major vessel. He collapsed to the pavement 20 seconds after he was hit and remained conscious for a few more seconds. This was after Coates shot his assailant, Richard Blackburn, 5 times with his service weapon. (Advance to 2:20 in the video to see Blackburn's attack (Coates is shot at 3:06 as he's radioing dispatch)). The Coates shooting is an illustration of what .22 is capable of when a vital structure is damaged.
Compare the shooting of Trooper Coates to the shooting of Chris Mercurio by an LASD deputy. (Video on
YouTube) Mercurio also collapsed about 20 seconds after being shot, presumably with 9mm. (Advance the video to about 6:45 to see the shooting).
A few years after the FBI's Wound Ballistics Workshop, Fackler reiterated:
"THE ONLY RELIABLE WAY TO STOP THE AGGRESSION OF A FEARLESS ASSAILANT IS TO DISRUPT HIS VITAL BODY STRUCTURES. This fact has proven itself both on the military and urban battlefields. It should come as no surprise to any experienced hunter.
"THE HEART, MAJOR BLOOD VESSELS, AND UPPER PART OF THE SPINE ARE THE VITAL STRUCTURES OF THE TORSO."
--Fackler, Martin L., M.D., "Police Handgun Ammunition Selection", Wound Ballistics Review, Fall 92, pp. 32 - 37.
Click here to read Fackler's paper.
Solid hits to the torso cannot be relied upon to instantly stop an attacker because blood loss takes time to be effective, even when a bullet(s) pass through the specific vitals Fackler identified (except spine). This is why we see so many police shootings involving multiple shots/hits. If the bullet(s) doesn't pass through one of these vital structures, then there's no physiological reason for an attacker to stop attacking.
I don't suggest .22 as a primary defense gun, unless it's all a defender can handle due to infirmities. A .22 is better than no gun or a larger caliber gun that cannot be shot effectively by the shooter. However, when it comes to caliber wars, I will always repeat: What you hit is more important than what you hit with.
[Edited to update the link to "Police Handgun Ammunition Selection"]