It’s interesting, even when you think you know a little bit about a topic you can run across information that causes a reevaluation of previously held opinions. There are a lot of myths when it comes to guns and ammunition. Perhaps myths is not a good word. Strongly held beliefs… things taken to be true… tropes. I have heard them all my life. Things like:

“If you shoot someone with a .25 ACP and they find out about it, they might get angry”

“A .380 ACP is either barely inadequate; or barely adequate”

“45 ACP: Because you don’t need double stacked fifteen round mags when you are carrying the Lord’s caliber.”

And when you read an article on handgun caliber, they typically list things from the smallest to the largest caliber, making relative comparisons a little difficult. At first it would make sense, the next bigger caliber is always more powerful. Is it? The length of the case/powder capacity also plays a very significant role. Also making things confusing, cartridge naming conventions are just all over the place. Really, the whole thing can make a person cross-eyed. So where are we going with all this? Things are not always as they seem, and internet lore is sometimes correct, and sometimes not. So what can we definitively say about relative handgun cartridge power? Well, it depends, but we can make some very good generalizations. The numbers used in the chart below are averages of several common factory loads for each cartridge. In some cases there are +p Loadings that are MUCH more powerful than average. In other cases modern factory loads are much weaker than the original loads. In the case of the .22LR they are loaded significantly hotter than they were 100 years ago. So absolute comparisons are difficult.

.22 LR – The .22 LR is an oddball. It is a rimfire cartridge, which means the firing pin strikes the rim (bottom outside edge) of the cartridge. This also means it is generally not reloadable, and especially in times past, they were not as reliable as a centerfire cartridge. But the .22LR soldiers on because it is cheap, effective in the proper context, and easy to shoot. In the early days of the 20th century a .22 revolver was was a popular “vest” gun. The interesting thing about the .22lr is that although it is most certainly not a powerful round, a lot of defensive situations have occured when a .22lr was used. Statistics show that it has reasonable one shot stop ability. This is just one of the interesting things about ballistics, not everything about a cartridge can be understood by looking at a piece of paper. No one would argue that a .22lr is the best self defense caliber available. But if it is all you have, all you can handle, or just simply what you can conceal because of your wardrobe that day, it seems to be much better than hurling insults at an attacker.

.25 ACP – Browning designed to mimic .22LR performance in a centerfire (reloadable, reliable) round. It has a reputation for being, well, crap. But, we just said above that Browning’s goal when he designed the .25 ACP was to duplicate the .22LR performance, and that the .22LR has a somewhat surprising one shot stop ability. What is the deal here? The first thing it seems, is that a 22LR was loaded lighter 100 years ago. Secondly, guns and ammo are a system. For legal reasons back in the mid to late 20th century it became impossible to import small, budget friendly pistols, but pawn shops could sell a lot of them. There were about a half dozen manufacturers that sprang up in southern California who made very inexpensive, generally low quality, very small semi auto pistols chambered in .25 ACP. The so called “Saturday night special” was born They sold really well. A lot of them were used in crimes and domestic disputes. They were generally unreliable over the long term. This caused the .25 ACP to get a very bad reputation. The problem now is that it is hard to find new high quality firearms chambered in this round. They do exist, but .22LR ammunition is less expensive, rimfire weapons are more reliable than they used to be, you can carry more .22LR than .25 ACP in a similar size gun, and so, .25 ACP is still not that popular.

.32 ACP / 7.65 mm Browning/ 32 Browning Auto – Around the turn of the 20th century .32 caliber revolvers were very popular so when semi-auto guns started taking hold it made sense to chamber them in a .32 caliber round. The first cartridge John M Browning designed for semi automatic pistols was the .32 ACP. In the early 20th century this was the most popular self defense caliber , especially in Europe. It remained extremely popular up until the 1950’s. It is effective within its’ limitations (bad word distances) and guns made for it are very concealable. The problem is that not a lot of manufacturers chamber pistols for this cartridge currently. There are a few though, Kel-tec P-32, Beretta Tomcat, Seecamp ($$), North American Arms and there are thousands of used ones on the market. The ammunition will be more expensive than .380 ACP, and the firearms chambered for .32 acp are not that much smaller than common pistols chambered in .380 acp.  So if you are shopping, perhaps think about buying a .380 ACP.  If you inherited one, or if it is all you have, it is certainly better than a pointy stick.

.380 ACP – Another round designed by Browning for his automatic pistol designs manufactured by Colt, if we used its’ metric designation we would call it a 9x17mm. Why the third digit, why is it a .380 ACP instead of a .38 ACP? Because there was a .38 ACP (9x23sr) that came first, now obsolete, and that cartridge, loaded hotter eventually became the .38 Super. The .380 cartridge uses a 9mm bullet diameter; not the same bullet diameter as .38 special/.357 Magnum.. In fact, some people call it a 9mm Short or 9mm Kurz (German for short). It has as stated above been thought of barely adequate or barely inadequate, but it has been used for decades and is in the same power class as the next cartridge, which was used as the premier police cartridge for 100 years. This is one of those internet lore things referenced in the beginning of the article. Within reasonable limitations and using modern bullet designs the .380 is capable of providing reasonable defense from evil doers. It would not be wrong to say that this is where “serious” self defense calibers start in the modern day..

.38 special (9x29mmR). This one is typically a revolver round. Why is it “Special”? Because it was more powerful than a previously created .38 caliber revolver cartridge (.38 Long Colt) which is obsolete now. This is a very old cartridge originally from back in the black powder days … and the bullet is not .38 caliber. It is actually .357 caliber in the modern naming convention. Got that? A .38 Special has a bullet of .357 caliber. If this old caliber was measured in metric units we might call it a 9 x 29mmR. The case is long because it was originally for black powder which was less efficient (larger granules with less power) than modern powders. So it is a big cartridge, but not very big power comparatively. The 38 Special is old and reliable. It was the gold standard for police and self defense calibers in the civilian world for around 100 years. It did not really become dethroned until the FBI and other agencies switched to semi-auto pistols in the late 1980’s. Yet, the modern consensus is that it is not powerful enough, “practice with .38 at the range, but defend yourself with a .357” is the wisdom of the day. That wisdom isn’t really wrong, but it isn’t the whole story either. The .38 special is good medicine for self defense, it works, and it is generally pleasant to shoot.

9mm, 9×19, 9mm Luger, 9mm Parabellum, 9mm NATO – Was developed in Germany by Georg Luger for his new pistol design a few years before browning developed the .45 ACP. 9mm round is now the most popular self defense, law enforcement, and military pistol caliber in the world. It seems to sit at the intersection of power and comfort. The firearms chambered for it do not have to be significantly larger than firearms chambered for .380 ACP. Although there are large percentage of tribal elders who will say that it is not powerful enough to ensure one shot stoppages; history has shown that the 9mm is enough gun. It is not too much gun, and in almost every instance it is plenty. If you notice in the chart, it is a pretty big step up in power from the .38 Special, a round that was considered the best police duty round for a very long time.  With modern bullets, in modern pistols, the 9mm will do its’ job if you do yours.  Also remember the chart is based on some generalities, there are many loads for the 9mm that exceed what is listed, further blurring the lines between the 9mm, the .40 S&W, and the .45 ACP.

.40 S&W (10×22mm) – The history behind this one is very interesting. The full story is too much for this article but the shortest version is that it was designed to be a more powerful than a 9mm option for the FBI. It was developed as a cut down 10mm. It fulfills its’ intended role, but after several years the FBI switched back to 9mm (and other Law Enforcement Agencies seem to be drifting that way as well).  The reasons for it gradually fading into the backseat are complicated, the primary one being that it is not significantly more effective than the 9mm with two downsides being it is a high pressure round that has a somewhat uncomfortable recoil, and the ammunition is more expensive than 9mm or .45 ACP.

.45 ACP (11.43×23mm) – This is another round with a fascinating history, but far too long to go into here. Suffice it to say that it has been over 100 years since its’ adoption by the US Military, and some units are still using pistols chambered for it. No one can doubt its efficacy. The cult with this one is as strong or stronger than proponents of 9mm. Either way, the .45 is a proven, excellent self defense round. It isn’t magical, and you won’t find many easy to conceal pistols chambered for it, but it is an excellent round whose lower chamber pressures can make it more pleasant to shoot than the .40 S&W, despite it being a little more powerful in most loads.

10MM Auto (10×25mm) – A cartridge forever tied to the invention of the .40 S&W. Originally conceived by Jeff Cooper as a way to get something approaching .357 Magnum power from a cartridge designed for a semi auto pistol: Mission accomplished.  It has a small but strong following. 10mm = .40 caliber, so they could have called the .40 S&W the 10mm Lite, or 10mm Short. I always wondered why the 10mm Auto was not called the 10mm Magnum. Who understands marketing anyway?

.357 Magnum (9×33mmR)- Another cartridge typically used in revolvers. The .357 is the original “Magnum”. The .357 is a much more powerful, ever so slightly longer version of the .38 Special. Why? Because originally some crafty old wizards loaded that long .38 Special case with more modern powders in modern, and stronger revolvers, to see how much more power they could get. The answer was a lot. But then they had a problem when it came time to make this new load commercially available.. Just because there were modern revolvers that could handle that much power, didn’t mean that the uninformed wouldn’t use that new load in an older, weaker revolver, and cause a safety issue. So they lengthened the case by a little bit to ensure that the new more powerful cartridge would only fit in revolvers capable of firing it. And for some reason…instead of calling it a .38 Magnum, they called it a .357. This is why any revolver chambered for .357 Magnum can safely and accurately fire a .38 Special. The .357 is more powerful than necessary, but not so powerful that it takes a gorilla to shoot it comfortably. It is an immensely useful cartridge, and a potent, possibly the best, man stopper.

As always, if you need help in choosing a firearm the folks at Liberty Tree are here to help.