It is safe to say that 9mm is the most common pistol caliber in the world. It is used the military, law enforcement agencies, and civilians all over the world, and is a very capable round.
9mm bullets are reliable, have real stopping power and is widely available, which makes it one of the best survival and self-defense calibers out there. Let’s take a deep dive into the history of the 9mm caliber and learn why it is so popular.
9mm bullets have been around for over a century, however, when someone talks about 9mm today, they mostly mean 9x19 parabellum. The round was initially developed by a German firearm inventor named Georg Luger, who developed the caliber for the semi-automatic Luger Pistol in 1902. The caliber has been used in a variety of different firearms since the beginning of the 20th century and is not showing any signs of slowing down.
The 9x19 parabellum is also known as the 9mm Luger, which was the name given to the cartridge for consideration by the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI). The name was later shortened to 9mm, and some people even call it nine these days. However, you'll still find that it is referred to the formal name of the caliber, 9mm Luger.
One of the main reasons for the extreme popularity and effectiveness of the 9mm cartridge is its ballistic performance. Ballistics generally means how much energy a bullet carries and transfers to the target, and how its trajectory changes.
Now, the ballistics of different loads of 9mm can vary significantly from each other, depending on a lot of features, like the bullet weight, its composition, the amount of propellant used in the bullet, and the firearm it is fired from.
However, the 9mm round is very capable in short ranges, and on average will drop only about 1.8 inches at 50 yards, in zero wind conditions. This means that the bullet travels relatively straight for the first 50 yards, which is longer than the typical range of engagements 9mm handguns, SMGs, or Pistol caliber carbines are used for.
At 100 yards, a standard 9mm bullet can drop more than 12 inches, which is a significant drop, but if you can land a shot at 100 yards, it does carry enough energy to still be lethal, and when fired from the longer barrel of an SMG of Pistol caliber carbine, shots up to 100 yards become much more practical with the 9mm cartridge.
So, even with handguns, 9mm is a very flat shooting caliber, and is deadly and effective in close ranges, apart from that, because of how easily available and affordable the caliber is, it is understandable why it is so popular and widely used.
Generally, there are dozens of different 9mm loads, but the most common ones you'll find in a gun store are full metal jackets, Jacketed hollow points, and frangible. Here is a brief explanation of each type.
Full Metal Jacket (FMJ) 9mm rounds, or as they are also called ball ammunition, are the most used 9mm rounds by civilians, law enforcement, and the military. These bullets have a lead projectile, with a metal jacket, usually made of copper. These bullets are relatively inexpensive and feed very reliably in semi-automatic pistols and even Automatic Submachine Guns (SMG).
The military exclusively used full metal jacket rounds for 9mm and every other caliber because of the Hague Conventions, since it is believed that hollow points and frangible bullets cause too much unnecessary damage.
Jacketed Hollow Points are very capable for self-defense, and close-quarters combat. Though FMJs penetrate more effectively, these bullets expand on impact, creating a larger world channel, and decreasing the risk of over-penetration as well. Therefore, it is a popular type of load used by civilians for self-defense, and law enforcement personnel as well.
These projectiles are also made of lead with a metal jacket but have a cavity in the nose, which causes the bullet to mushroom on impact.
Frangible bullets are ideal for shooting at the range, as they have very low penetrating power, and completely disintegrate upon impact, eliminating the risk of ricochets and fragmentation. These rounds are also used for shooting pests at farms and are often considered less effective for self-defense.
If you have ever gone to a gun store to buy ammunition, you have probably noticed different grain numbers of different boxes. Many people make the mistake of thinking that grain has something to do with the amount of powder in the bullet, however, it actually represents the weight of the bullet itself.
A grain is a Troy weight measurement, which is used to measure small quantities of metals. For reference, 437 grains make up one ounce. The number of grains you see written on a box of bullets represents the weight of the projectile and not the entire cartridge. So, a typical 124 grain 9mm bullet, will have a 124 grain or 0.28-ounce projectile.
Now, the weight of the projectile can have a lot of impact on the ballistics of a bullet. It can change its trajectory, the way it impacts a target, its accuracy, and the recoil impulse it generates.
All 9mm bullets have the same dimensions, which means that bullets with a higher grain weight pack that weight in the same dimensions. So, when a heavier projectile impacts a target, it is obviously going to carry more energy and do more damage. However, heavier bullets drop more quickly as well, so they are less accurate at longer ranges, for the same amount of propellant, because in some cases, you can also get 9mm+p bullets, which are pressurized and sometimes have more powder. These bullets are faster and have a stronger recoil impulse as well.
Generally, a caliber like 9mm is compared to other common calibers, like .40 S&W and .45ACP, however, when talking about size and performance, the calibers closer to 9mm are .380 ACP and .357 Sig
The projectiles on all these bullets are very similar; however, 380 ACP is shorter, has less recoil, and is cheaper to produce. It is also a quite popular self-defense caliber in the US, but it isn't anywhere close to 9mm, and doesn't have the same stopping power.
The .357 Sig is a relatively newer cartridge but is faster and performs better against body armor. Though the new Sig M17 or P320 can be modified to fire the .357 Sig, the army still adopted the pistol in 9mm, making it the king of pistol calibers.
Reloading 9mm rounds is very popular, and though 9mm is generally an affordable and easily available round. With the recent ammo shortages in the US, more people have started getting into reloading.
Reloading 9mm is very easy, since you can easily find Brass and Bullets for 9mm reloading. Rounds like 357 Sig are a little more expensive, you can also find 357 SIG Reloading Supplies, which makes them more affordable to shoot, and of course, they also have better performance than 9mm, but the availability isn't as easy.