I want to talk about something today that comes up any time defensive carry ammo is brought up. The “Great Caliber Debate” !! There is an enormous amount of data out there now about various calibers, brands, and weights of ammo. A lot of that data is ballistic gel penetration data and other measurable changes in the bullet and its interface in a lab setting. Some of that data includes a chart that Greg Ellifritz put together that shows real life results. (listed below in the link)
I think it is imperative to remember that all these data are missing something. The effect of Accuracy. We know, more or less, what a bullet will do to its target. We know, more or less, how many people are shot by, wounded, or killed by which caliber of bullet. But the thing that is not present in the data is the quality of marksmanship. Another significant piece of data that is missing is the ability to know what might have taken place between shots if the follow up shot had been slower. Would the person shot have quit or died without a follow up? We don’t necessarily know.

Another important thing to internalize is that, as a defender, our goal is not to kill the bad guy. We are not the judge and executioner. Our goal is stop the threat. Often, that results in their death, but it is not our intent. So when we are choosing a self-defense round we want it to be able to do a few things (not necessarily in order):

1. Stop the threat ASAP to degrade the bad guy’s ability to shoot back at us.

2. Stay in the threat so the risk of a pass through and subsequent injury to an innocent is minimized.

3. Have accurate and predictable ballistics from our firearm.

Can a .22 stop a threat? absolutely. Will it stop a threat as quickly as a 9mm or a .45 death ray? maybe. If it’s a psychological stop, there might not even be a statistical significance. Will a .22 result in a forced physiological stop as fast as a 9, 40, or 45? Maybe not. The accuracy will be more important. The energy transfer is going to be much less.

But Rosenberg, if you think that size matters (it does) then why do you carry a 9mm instead of a .45? Well, because the 1st shot may not be the end of the fight, and I can put 9mm on target *accurately* faster than I can with a .45. So say we look at hole size in the target. I can’t guarantee expansion will occur so we will have to go by caliber width unexpanded.
If I can shoot 3 accurate 9mm (0.354 caliber) rounds in the time I could shoot 2x .45 whats the total hole size? 0.354 x 3 = 1.062″ BUT 0.45 x 2 = 0.9.” The longer the fight goes on the greater the disparity. So, am I really winning the size game with a .45?

There are dudes out there who can shoot a .45 at the speed of human limitation. I am not that dude. I can, however, run more than a few rounds of 9mm accurately at the speed of my OODA loop. (0.25-0.3 second splits) A little faster if I don’t have to complete the “decide” part of loop due to proximity. Can I shoot .22 faster than 9? yes I can. But I can’t engage my OODA loop any faster than I already am so I wouldn’t shoot it faster anyway. And then there is still the question of energy transfer. Moot point.

So what is the best? Well, it needs to meet our 3 important criteria. Then, I would consider how big the total hole size is for the relative time of 3 rounds on target accurately. In my opinion, with proper training 380 ACP or larger should accomplish this for you. Your handgun is only as effective as the ballistics it can deliver accurately. optimize your chances at surviving a deadly force encounter by having an effective weapon system.

Copywrite 2019 Kjell Rosenberg
https://www.buckeyefirearms.org/alternate-look-handgun-stopping-power