This is one of the biggest debates in the whole realm of firearms users, whether it's military, Law Enforcement, hunting, or self-defense for those who chose to either carry one, or have one in the home for self-defense. There are those that believe that it must be .40 or greater or you're just wasting your time, there are those that believe a handgun isn't big enough at all you need a rifle or shotgun, and then those that believe any caliber works as long as you have a gun for protection. Well, They all are right! To a certain degree. We're going to go over some different theories and statistics here. Theories are great on paper but not good in the real world unless they become statistically true.
We will start with "knock down" power. It is said that you only have "knock down" power with a .40 and higher handgun. Well, this is a myth. A handgun doesn't have knock down power. I have never read of a case of a handgun knocking someone down with the pure force of the bullet hitting them. Want proof? Check out the video of a guy shooting himself at point blank range with a .44 magnum. A handgun doesn't get much more powerful, especially in one you can conceal carry.
This video is proof that knock down power from pure force of the bullet hitting someone doesn't exist. So, the whole you don't have knock down power unless it is .40 or higher is busted. If you want true knock down power get a baseball bat or sledge hammer.
Now, since our classes are based on handguns only we're going to stick to the handgun with this segment. We will do another for rifles and shotguns later.
The bullet caliber must be a 9mm or better to have "stopping" power. Well, even though the way a lot of people think of stopping power is a myth since it would fall under "knock down" power. There are true stop shots or points on the human body that if hit they will stop instantly. These places are the Spine, Hips, and Head. These are the only guaranteed places that will actually stop and attacker instantly. Please see shot placement for more info on this. These places are instant "down" hits. The one thing to know is that it doesn't matter how big the bullet is hitting these places, what matters is that the bullet went deep enough to hit and penetrate them. At point blank range any caliber would do the job, however the further away the attacker is the bullet would have to have enough power behind it to propel it to the attacker and through to these areas. The further away the attacker the faster the bullet would have to be. I wouldn't want to be in a shoot out with an attacker at 75 yards with a .45 because it's too slow to do any damage at that distance. So, now it becomes more about shot placement than bullet size.
Well, You ask what about internal damage to stop the attacker. Ok, legitimate question. There are 2 things we need to look at with this. The first being how much damage by shear force will a bullet cause? Well, the force in itself will cause a temporary wound cavity which would be like a force trauma jolt to the body. If you view the video below you will see the initial expansion of the ballistic gel.
This would effect your organs, blood vessels, and surrounding tissue. The more expansion the more damage to the body there theoretically should be. If you go to the shot placement page and see the guy shot 14 times with a .45 ACP and 13 of them being "vital" hits should have caused great damage and should have stopped the attacker and didn't. Due to the attacker being hopped up on some kind of drugs it didn't stop him the way it theoretically should have so we can't count on this theory. Due to the likely hood of your attacker being on drugs being great this can't be counted on.
The next video shows that it's speed over size that causes more damage overall but if you can get the big calibers to go fast it will cause even more damage. A 9mm has a fps of around 1250-1300 while a .45 has an fps of 850-950. So the big bullet is equaled with overall ballistics because the 9mm is faster. If you can get the .45 to around 1150-1200 fps it would do much more damage.
This shows the .22lr a diameter of .222 and weight of 40 grains and the .223 with diameter of .223 and 55 grains. Almost same diameter with a little weight difference but different speeds and way different power. The .40 and .351. A difference of .049 diameter but same weight. Again, different speeds and way different power.
The next in this would be "total bleed out". This is when a person looses so much blood that they can no longer function. In theory this is 6-14 seconds for a normal human being. In theory the bigger the hole the faster they'll bleed out. Well, this does have truth to it. The bigger the hole the more blood will come out of it. The same as the more holes the more they will bleed out. So, not taking hollow points or expansion in to factor (which needs to be done, but since each different manufacturer's hollow point is different we're just gonna go for basic size) the larger .45 would allow more blood to flow out than a smaller caliber would. Again, with your attacker on drugs this can't be counted on. The chart below shows caliber, accuracy, stopping power, one stop shots, etc.
Based on this chart all of the calibers do the job, and actually did it well. With studying this chart and other statistics we come to the conclusion that the reason the higher calibers are equal is because of missed shots, and the lower calibers are much higher than you would think is better hit percentages and better shot placement. The one stop shot percentage had to be as high as it is for the .22 for a couple of reasons. 1. The bullet hit a stop shot area, spine, hips, head, or the simple fact that the attacker stopped when he saw he had been shot. The higher calibers not having any better results had to be misses and poor shot placement. I can give 2 examples of this off the top of my head both involving trained police officers. One is the one with the .45 that hit the attacker 14 times with 13 "vital" hits. The officer actually shot 35 shots so he missed 21 times. The other is a shoot out occurred with 1 attacker and 4 police officers with .40 caliber handguns. The officers fired 36 shots and hit him 4 times. Now the 4 hits were enough but it took 36 overall shots to stop the attacker and in this instance the 4th hit was through the throat and hit the spine.
What does ALL of this tell us. First, shot placement is number 1. Shot placement trumps everything else in the handgun world. Nothing else comes close. Second, knock down power in a handgun does not exist. Third, we can't count on the pure force of the bullet penetration to disrupt the organs and blood flow enough to stop and attacker. Forth, we can't count on our attacker to bleed out fast enough to stop before he kills us. Well, OK. Now what?
Our suggestions off what we have found. Outside of the Law Enforcement and Military realm. The basic armed citizen using their handgun for defense weather inside the home or out and about. We suggest finding a handgun no matter the caliber that you are comfortable with carrying, shooting, and can become very accurate with shot placement and use it. We always suggest to our students to start at a full size 9mm and go from there. If it's too much go down if it's not and they want bigger, go bigger as long as they can have precision accuracy with it. Precision accuracy comes with practice, see other pages. I personally suggest getting the best all around round for the job that works for you. If you can't hit a target with anything outside of a .22lr with good accuracy go with that. Imagine how hard a moving target will be. If you are great with a 9mm but only so so with a .40 stick with the 9mm. You will be able to hit stop shots and you'll be able to hit them more times which ups your chances of a stop shot. Don't over caliber yourself, it will be better to under caliber than to over caliber.
Caliber is a great distant 2nd to shot placement.
With this you ask would you carry a .22lr being confident it will protect you and your loved ones? YES. My shot placement is great with a .22 and I have no doubt that I can stop them with it. Do I carry a .22 for protection? not usually, I carry a .357 sig most of the time. I have great shot placement with it, it hits hard, and leaves a big hole. I have all of the factors, shot placement, force, and hole size with it. For me it shoots better than the 9's, 40's, and 45's. Has better handling than any of them to me. I'm very comfortable with it, can hit a moving target multiple times very accurately. However, I do carry a .380 at times and I will carry a pocket .22 at times depending on how I dress.
The bottom line is this. Carry what YOU are comfortable with. Not what someone tells you that you need or have to have. Nobody can tell YOU that you will be comfortable with a certain gun or caliber. Don't go off the myths of knock down power and that bigger is better. The video and chart above disproves this. I was always told this and believed it until I started doing research for myself. Don't just take my word for it, do your own research but get good data. There is a lot of data and videos that lean towards the persons favorite caliber. They will like the .45 so they'll get great .45 rounds and bad 9mm rounds to offset the data and the 9mm guys will do the same to put the data in their favor. Start researching gunshot deaths and get your own statistics and it will show that all calibers are equal in lethality across the board.