Quick, which caliber is better for self-defense, 45 ACP or 9mm?
45 ACP is bigger!
9mm has a high capacity!
What if I told you it doesn’t really matter? That with modern defensive ammunition the war between 45 ACP and 9mm is largely indifferent. In fact when it comes to most calibers size rarely matters in the first place when it comes to hitting a bad guy and putting him on the ground. Certain calibers certainly have some advantages in different situations.
For example 40 S&W and 10mm have better barrier penetration that 45 ACP and 9mm.
45 ACP is the easiest pistol caliber to run suppressed.
And 9mm does have the most capacity.
7.62 NATO is a better cartridge at longer range than 5.556.
These are all advantages to that particular caliber and in certain situations are advantageous. However, if we get into simply gun fighting bad guys, and what’s capable of stopping them the size of the round really doesn’t matter much. There is no such thing as ‘stopping power’ and most modern ammunition will put a bad guy down.
So why don’t we all use 22 LR and call it a day? Well, first off rimfire isn’t that reliable. Secondly, the round does need to have enough mass and velocity to penetrate deep enough to strike a vital organ. The FBI uses ballistic gel to determine how deep a bullet can penetrate, and they require their rounds to penetrate at least 12 inches of ballistic gel. The smallest caliber that reliably penetrates 12 inches of gel is the 380 ACP and that is only in certain loads.
Size matters to a degree, but only to the degree, the bullet can penetrate after being fired. For prepping and SHTF type scenarios I typically advise 9mm and up, for reliable penetration. What is more important than bullet size is shot placement.
Shot placement is the ability to hit a vital area of the body. Poor shot placement is a shot that does not have an immediate, or near immediate effect on the threat. Shot placement is important not only for self-defense but for hunting animals as well. Your goal regardless of what you are shooting is to stop your target as quickly as possible.
This means targeting the most critical organs that you can accurately hit. This is why we write off the headshot for most shooting situations. Heads are small targets that are easy to miss, and you are responsible for that projectile when you miss. This leaves us with the heart and lungs, positioned conveniently in the center mass of most living creatures. Shooting at center mass and aiming for the heart and lungs bleeds into the concept of aim small, miss small.
This means you aim a smaller target within your target. So if a deer is your entire target, aiming at the heart and lungs is the aim small concept. This means when aiming at the deer’s heart if you miss the heart you are still likely to hit the animal, this is the miss small concept. So even if you miss the heart, but hit the target it is wounded, and the shot you fired is accounted for.
On the Human Predator
I’m not teaching you anything new here when I say the lungs and heart in a human are in the chest. In most situations aiming at the chest is the most natural shot to take. When you expand your arms forward they are most often in line with most people’s chest.
Let's say you can’t target the chest. For example, they are wearing body armor. In this situation, it is still a good idea to hammer them in the chest. Armor may save their lives ultimately, but it is going to hurt pretty bad even through armor. This knocks them off target and allows you to target a vulnerable area. Primarily the head. If you are close enough or skilled enough to target the head this is the preferred option.
Alternatively, if you don't feel confident in a head shot, or because there are innocents behind the threat, you can go for a pelvic shot. The pelvis is basically a load bearing wall of the human body. Hitting this area is unlikely to kill your opponent but can incapacitate and immobilize an opponent. Since the pelvis is often at a downward angle of aim if you miss the projectile is likely to strike the ground.
Most animals in the United States that have four legs are easily dispatched with most common calibers of firearms. Very few animals require a magnum caliber rifle to dispatch. Some animals, like bears, are not easily dispatched via standard handgun but can be dispatched by most full-powered rifle rounds.
The key to success is striking the same heart and lungs. This is a more humane and more efficient method to bring down game. Typically right behind the front legs lay the heart and lungs of an animal. A well-paced shot this area will often take the animal down almost immediately. If the animal is facing you, you can usually reach the heart easily though the front of the chest.
Before it was called shot placement, and there was a science behind it, people simply used to say shoot what you can hit your target with. It's simple advice, and it’s easy to follow. Carry a caliber that can reach the vital organs, and then learn to use it.