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9×18 vs 380 Ammo: Are they interchangeable?

There’s no shortage of self-defense ammunition in the US, though many individuals aren’t quite sure whether the standard 9 mm cartridge is the end-all-be-all for their needs. There are two alternatives you may not have heard of: the 9×18 Makarov and the .380 ACP.

Both of these cartridges are fairly similar, being around the same size and featuring similar ballistic power profiles. But there are some differences you should be aware of before purchasing one or the other.

Today, let’s take a closer look at the 9×18 Makarov versus .380 ACP ammunition in detail.

Are the 9×18 Makarov and .380 ACP Interchangeable?

No, the 9×18 and 380 are not interchangeable. Although the 9×18 Makarov and .380 ACP cartridges seem to be almost identical, they do have a number of significant differences that make them incompatible with each other’s firearms.

The .380 ACP cartridge’s caliber is .355” while the 9×18 Makarov’s caliber is .365”. Thus, they are slightly different sizes overall. Remember, this was intentional on the Makarov designer’s part. Additionally, the Makarov case is normally tapered, whereas the .380 ACP cartridge’s case has straight walls. The other dimensions of both cartridges are also dissimilar enough that you can’t use the cartridges in the exact same pistols.

9×18 Makarov Overview

9x18 Makarov Ammo

The 9×18 Makarov, also called the 9mm Makarov or 9x18mm PM, is one of the most popular Soviet submachine gun and pistol cartridges. It was originally developed toward the end of World War II in 1946. The 9×18 Makarov was intended to be a powerful cartridge that wouldn’t produce too much recoil when used in a typical blowback pistol of the time.

Interestingly, the 9×18 Makarov was also designed with a slightly large than average caliber, .365”, so that the Germans, were they ever to invade Russia again, could not use the rounds in their 9 mm weapons.

Yet it wasn’t until 1951 that the 9×18 Makarov, and its similarly named pistol, were accepted and widely used in the Soviet army. With a standard load of 95 grains and a typical muzzle velocity of 1050 ft./s, the  9×18 Makarov has a typical effective range of about 50 m or 55 yards.

Case typeRimless, tapered
Bullet diameter9.27 mm (0.365 in)
Land diameter9.00 mm (0.354 in)
Neck diameter9.91 mm (0.390 in)
Base diameter9.95 mm (0.392 in)
Rim diameter9.95 mm (0.392 in)
Rim thickness1.25 mm (0.049 in)
Case length18.10 mm (0.713 in)
Overall length25.00 mm (0.984 in)
Case capacity0.83 cm3 (12.8 gr H2O)
Rifling twist240.00 (1 in 9.45 in)
Primer typeBerdan or Boxer small pistol
Maximum pressure162.03 MPa (23,500 psi)

Where Can You Buy 9×18 Makarov?

As mentioned, the 9×18 Makarov was designed in Russia, so most manufacturers of the cartridge are from the Eastern Bloc and similar locations. That being said, you can easily find 9×18 Makarov ammunition from online gun ammunition stores and/or marketplaces. Some US retail stores may also carry 9×18 Makarov ammunition if they sell pistols or submachine guns chambered for the cartridge.

.380 ACP Overview

.380 ACP Automatic Colt Pistol cartridge ammo

The .380 ACP or Automatic Colt Pistol cartridge is a rimless straight-walled pistol cartridge developed in 1908. It was originally intended to be used in the Cold Model 1908, though it has since become one of the most popular American self-defense cartridges of all time. It can even be used in modern handguns (especially smaller pistols).

The .380 ACP cartridge also typically fires a 95-grain bullet, though it has a lower average muzzle velocity compared to the 9×18 Makarov: 980 ft./s. However, some American manufacturers like Buffalo Bore produce specialized versions of the .380 ACP cartridge with higher than average muzzle velocities, like 1125 ft./s.

As a similarly low-powered handgun cartridge, the .380 ACP cartridge has a maximum effective range of between 50 and 100 yards depending on the exact firearm and the skill of the shooter.

Case typeRimless, straight
Bullet diameter9.0 mm (.355 in)
Land diameter8.8 mm (.348 in)
Neck diameter9.5 mm (.373 in)
Base diameter9.5 mm (.374 in)
Rim diameter9.5 mm (.374 in)
Rim thickness1.1 mm (.045 in)
Case length17.3 mm (.680 in)
Overall length25.0 mm (.984 in)
Maximum pressure148 MPa (21,500 psi)

Where Can You Buy .380 ACP Ammo?

.380 ACP ammunition will be a lot easier to find in America due to its American origin. Indeed, you can find .380 ACP ammunition in almost every retail gun shop in the country, provided they have classic gun models like Glocks and Remingtons available to take it.

Additionally, the .380 ACP cartridge can be found at a variety of online marketplaces and stores for cheap. Both cartridges can be purchased at a discount if you buy the ammunition in bulk, which is true of most gun ammo overall.

What is Each Cartridge Ideal For?

Both the 9×18 Makarov and the .380 ACP are largely intended as short-range, self-defense pistol cartridges. To that end, you can slot them in firearms like pistols and submachine guns of similar sizes.

The 9×18 Makarov, for example, is commonly used in pistols like the Makarov PM, the P-64 Pistol, and the Grand Power P9M. The .380 ACP cartridge, on the other hand, is used in pistols like the Glock 42, the Remington Model 51, and the Kel-Tec P3AT.

Both cartridges have enough stopping power to serve as suitable self-defense projectiles. When shooting center mass, one or two cartridges should be enough to take down an attacker. Both cartridges are also fairly accurate within their effective ranges. You may be able to use the 9×18 Makarov and .380 ACP cartridge for small varmint hunting on your property.

That said, the 9×18 Makarov cartridge is about 10% more powerful compared to the .380 ACP when measuring ballistic power directly. The 9×18 Makarov cartridge is also typically cheaper and easier to find online, though you may have more difficulty finding it in-store in America due to its Eastern Bloc origin.

Wrap Up

As you can see, the 9×18 Makarov and .380 ACP cartridges are pretty similar, though they retain a few major differences that prevent them from being used in the same firearms flat out. Still, you can choose either cartridge and expect them to perform in the same way and do the same things.

Both the 9×18 Makarov and the .380 ACP are ideal self-defense cartridges to use for property defense or for use in concealed carry pistols. Due to their ubiquity and affordability, you can easily stock up on these cartridges and ensure you have plenty of ammunition for the foreseeable future.

Both cartridges can also be used for short-range hunting or varmint clearing, or for target shooting in your backyard or at your local gun range. Bottom line: just make sure that your pistol is chambered for the right cartridge since loading your weapon with the wrong ammo could lead to a malfunction.

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