A Girl and Her Gun was talking about shooting an XD 9, and while we were discussing it in the comments she mentioned this.
I also looked up 9x19mm just to see if that was different from what I have been referring to as 9mm. While reading about it I came across the term Parabellum which is derived from the Latin: Si vis pacem, para bellum, which means “If You Seek Peace, Prepare For War”. I am sure everyone here knows that, but I had never heard of it and I love it. Might become my new motto. Well, I guess it has been my motto, but this says it so nicely.
Heh, that’s one of the pains-in-the-ass with talking guns to newer shooters, some of the more common cartridges have LOTS of names. I know I’ve talked about it before, but I like this subject so allow me to prattle.
Say the 9mm cartridge introduced by Luger at the turn of the last century, damn pill has a HUGE number of names. 9×19, 9 mm Luger, 9 mm NATO, 9 mm Parabellum, 9 mm Para, and just 9mm.
All of those are acceptable names for the same cartridge. They are 100% interchangeable, as the NATO load is a bit more powerful than the traditional loading, but overall they can be considered interchangeable.
How do these names come about? Well as a general rule the formula is Width of the bullet, either in millimeters, or in inches (note that Inch designations there is a decimal point, and this number is often refereed to as “Caliber”), then followed by a name chosen by the originator…or in the case of older cartridges, adopters.
It appears that the origonal name for this round is 9mm Parabellum (As the lady notes Latin for “Prepare For War”) but it was invented by the people at Luger, so its often called that. It was later adopted by NATO forces as their chosen pistol cartridge, hence the NATO name. Now what about the 9×19 one? We call that European Designation, and some may have noticed that I find it rather elegant in its consistency and information conveyed. That is the measurement of the bullet (only in millimeters) followed by the length of the cartridge casing from the Head (which is the bizarre name for the flat part on what I consider the bottom of the cartridge where the primer lives) to the case mouth, also in millimeters.
This is useful because it can convey a ton of information if you don’t know the cartridge. Like let’s talk about 9mm Largo (If you aren’t familiar with it don’t click the link just yet). Now the name doesn’t tell us much, just that it, like the Luger Round fires a 9mm bullet. Still if I told you 9mm Largo is also known as 9x23mm suddenly you know its a longer round, and by virtue can guess that its more powerful. Those are both true…tho not always. The old black powder revolver cartridge .38 S&W (Not to be confused with the modern .38 S&W Special AKA .38 Special) is 9x32R (“R” designating that the cartridge has a rimmed base), but that extra case length was developed for Black powder, not smokeless, so smokeless loadings of the same pressure are VERY light.
While every cartridge can be converted into a European designation, you won’t read many “9x32R” when talking about older S&W revolvers, nor will you ever see 11.43x23mm when talking about one of my favorite pistol cartridges.
Now let’s get into some errata. The numbers are not concrete scientific numbers. Like let’s talk about 9mm bullets. If say we were to take some common 9mm calibers. 9mm Luger, .380 Auto, .357 SIG, and 9mm Makarov. (9×19, 9×17, 9×22, and 9×18 respectivly) the first 3 all use 0.352″ bullets at various weights, and pushed at various speeds….but the Russian Makarov uses a 0.362″ bullet.
Also people new to revolver shooting will quickly realize that a .357 Magnum revolver can camber a fire .38 Special cartridges….but .38 and .357? Well in fact both bullets are 0.357″ (which is also “9mm”) but the .38 Special has some old history that is better explained here.
Oh and just because a bullet is called X does it mean ANYTHING, there are no rules as to what you call a new cartridge. Like .460 S&W Magnum, its based on the .45 Colt cartridge, and can chamber and fire .454 Casull cartridges….both use 0.454″ Bullets but S&W called it “.460” probably because “.454 Magnum” or some such would sound too similar to .454 Casull. And probably why .454 Casull didn’t just call itself “.45 Magnum”, or “.45 Casull”, one is allowed a certain amount of flare.
Also some names are associated with specific loads or pressures, the most famous are the NATO loads. Seems when NATO adopted various cartridges they decided to be different when it came to cartridge pressures…and decided to not be consistent on how they changed it. 9×19 NATO and 5.56x45mm NATO are both slightly more powerful than commercial 9mm Luger and .223 Remington…but 7.62x51NATO is LESS powerful than .308 Winchester….tho all of those cartridges are the same in overall dimensions.
This is why I’m so amused by this subject, as there is SO much to talk about, and there is so much history, marketing, and “Why not?” thrown in there.
And guns are fun!

