Intro: What caliber a person feels is the “best” for any particular usage in a handgun is a very complicated and touchy subject for firearms geeks. It is a potentially confusing topic to those who are just getting into firearms. It is arguable that there is already a good caliber or two (or three) for every potential purpose. However, emotions get involved in the discussion at times and opinions run strong. Any handgun is a compromise; carrying around a rifle would be better. But it is impractical to take your AR out on the town. So the question with a handgun becomes ‘what weapon can I comfortably carry and still have an effective means of defense?’ The decisions one has to make when carrying a handgun are the compromises between power, portability, fit, and capacity. Everything is a tradeoff…
So…What’s so great about the .9mm?
When we begin trying to choose a suitable self defense caliber we have several things to consider. On one hand we want enough power to do the job, but not enough to cause discomfort on the part of the shooter. We need the power, but we also need the gun to be portable. Big cartridges require bigger guns. Smaller cartridges are (generally) less powerful but allow smaller guns, however smaller guns often result in less pleasant recoil. So there is a limit to both what the shooter can comfortably shoot and carry. The grip of the gun has to fit. This is a very personal and subjective measure. But the fact is if everyone had the same physiology then there would only be one style grip on a firearm. Lastly we need to have a certain number of follow up shots. This compromise must exists because a human hand can only control so much force, because a bullet’s speed and size is what makes it work, and because if capacity didn’t matter we’d all be carrying derringers.
Called the 9×19, 9mm Luger, 9mm Parabellum, 9mm NATO; they are all the same (mostly) – The 9mm round is the most popular self defense, law enforcement, and military caliber in the world. It has been around since the dawn of the 20th Century. 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. But there are large percentage of tribal elders who will say that it is not powerful enough to ensure one shot stoppages. Maybe, then again, maybe not. There is a phenomenon in the tribal consciousness, and especially on the interwebs, that I call the “Moar Powa” phenomenon. It goes something like this: the .380 acp is not powerful enough, the 9mm is barely powerful enough, the .40 is just powerful enough, the .45 is all you really need, the .357 is the best there is, but what you really should be carrying is a .44 magnum, but I read one time where this guy was shot 4 times with a .44 Magnum and walked it off (no, not really) and so now I carry a .500 S&W.
Detour: There is a race in any geekdom (and that is what a large percentage of firearms enthusiasts are: geeks, author included) to have the biggest & bestest & mostest. It is the same reason that you see pickup trucks that require a step ladder to get into and have smokestacks bigger than an ocean liner. It is the same reason that some people have stereos that loosen your fillings from two lanes over and five cars behind you at the light. It is why Lamborghini cars exist. I suspect that in any specialized interest this phenomenon exists; Computers, Gaming, Photography, Fashion, you name it. Back to the story…
The 9mm Luger was a further refinement of a lineage of pistol cartridges which were developed from the 8mm Mauser rifle cartridge. It was designed by Georg Luger, hence the name, but he called it the 9mm Parabellum. Parabellum is in reference to the Latin phrase Si Vis Pacem, para bellum, which means, “if you seek peace, prepare for war”. It picked up the NATO classification when it was adopted by NATO as the standard sidearm, more on that later. The 9mm was the sidearm of the German aligned allies in both big wars, and afterwards it became the most popular military sidearm round throughout Europe. It was there in the trials when the US selected the 1911 and the .45 ACP. However after designing the 1911 for the .45, the esteemed John Browning designed a pistol, the Hi-Power, for it. The Hi Power went on to become the most popular military sidearm outside the US (Sadly Browning is ceasing production of this icon). The 9mm was adopted as the NATO standard in the early 80’s (side note: this is a very interesting tale as well, long story short we agreed to the 9mm because we forced NATO to accept the 5.56 as the rifle round) and started becoming popular with Law enforcement and civilians in the US in the 80’s and early 90’s. It is important to note that the civilian version (9mm Luger or Parabellum) is loaded to a lower pressure than the 9mm NATO version. The 9mm NATO is roughly analogous to higher pressure civilian load 9mm Luger +P.
In the 1990’s the wündernine revolution took off in real earnest with the polymer pistol invasion started by Glock. The combination of the modern polymer frame, striker fired pistol, carrying over 15 rounds of ammunition in a reliable, concealable, handgun forever changed the firearm industry. Part of the reason it is so successful, is simply because it is so successful. Manufacturers debut almost every new pistol in 9mm, ammunition is made by the train car load, the economy of scale make it less expensive, the pistol and ammunition sales drive more R&D into the 9mm cartridge, which makes it more effective, and more popular. But, all this aside, history has proven that one reason it is popular is that it works. The 9mm is enough gun. It is not too much gun, and in almost every instance it is plenty. Out of a gun with a 4” barrel common loads will average about 400 ft lbs (~550 J) at the muzzle, where a .45 ACP generates about 450 ft lbs (~610 J). Comparing the recoil of these cartridges in fully loaded Glock 19, 22, and 21 pistols, we see that the 9mm Luger generates ~66% of a .45 Auto’s recoil, but delivers ~95% percent of its kinetic energy and ~70% of its momentum. Not bad at all.
The .40 S&W was built as a compromise cartridge (for the FBI) to offer more power than the 9mm, with less recoil and more capacity than the .45. Since 1990 it has been the darling of law enforcement. But that’s changing, part of the reason for this is because of bullet advancement. It is not as though the 9mm has caught up to the .40; that is a common misunderstanding. Advancements in bullet and powder technology help every caliber (but it is fair to say that not all receive the same level of research attention). The fact is, the 9mm has caught up to about where the .40 S&W used to be, that is to say, it performs now about as well as the .40 S&W did when it was introduced. If the 9mm now can safely meet the performance parameters that the .40 was created to meet; why do we need a larger, more expensive bullet that is usually minus 1 or 2 in capacity of a similar sized firearm, has more recoil and uses more raw materials?
The FBI switched back over to 9mm a couple years ago, for the reasons stated above, in addition they have studies that show that under extreme stress even trained agents miss a lot (a lot). Therefore their belief is that follow up shot accuracy and capacity are important. To put it succinctly: the only bullets that count at all are the ones that don’t miss. In 2017 the US Military went through a very lengthy process to choose a new sidearm, and possibly new official cartridge. After testing, they stuck with the 9mm, and chose a Sig, polymer, striker fired, double stack pistol.
The 9mm vs .45 ACP debate will never end, like Mac vs PC, Apple vs Android, Ford Vs Chevy. Canon vs Nikon. It keeps life interesting. But one thing is certain, the 9mm will continue to be the most popular handgun caliber throughout the world for the foreseeable future.