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Can You Shoot 380 in a 9MM? What You Should Know

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Many wonder if they can shoot .380 ACP in a 9mm firearm since the cartridges look similar. In reality, they are quite different. You should understand how they are different and the potential dangers associated with using the wrong cartridge in your firearm.

You cannot shoot .380 ACP in a 9mm firearm, or vice versa. The .380 ACP and 9mm cartridges have different case dimensions, bullet diameters, and pressures, making them incompatible. Using the wrong ammunition could damage your firearm or injure you. 

An avid shooter for some 25 years, I can personally describe the differences between the .380 ACP and 9mm cartridges. In this article, I will explain the potential dangers and consequences of using the wrong ammunition and how to ensure you use the correct ammunition for your firearm. Follow this guide to stay safe when handling your weapon and avoid potential mishaps.

What Are .380 ACP and 9mm Cartridges?

9mm Ammo and Firearm

Here is an overview of the two cartridges. 

.380 ACP Overview

The .380 Automatic Colt Pistol (ACP), also known as the .380 Auto or 9mm Short, is a popular cartridge designed by John Moses Browning. I prefer to use this cartridge in compact and subcompact handguns due to its smaller size and lower recoil than the 9mm. Specifically, I use the .380 ACP for self-defense and concealed carry purposes.

9mm Overview

The 9mm, officially known as the 9x19mm Parabellum, is one of the most popular handgun cartridges in the world. Designed by Georg Luger, the 9mm is known for its versatility, relatively low recoil, and high capacity in compact handguns.Law enforcement and the military use it extensively, as well as civilian shooters.

Differences Between .380 ACP and 9mm Cartridges

Though the .380 ACP and 9mm look similar, they have several key differences, including case dimensions, bullet diameter, and chamber pressure. You must understand these differences to understand the compatibility—or lack thereof—of these two types of ammunition.

  • Case dimensions: The .380 ACP is 17.3 mm (0.68 in) long, but the 9mm is 19.05 mm (0.75 in) long. This difference in case length affects the overall cartridge length, so it’s impossible to chamber a 9mm cartridge in a .380 ACP firearm and vice versa.
  • Bullet diameter: The bullet diameters for both cartridges are nearly the same. The .380 ACP has a diameter of 9.02 mm (0.3551 in), while the 9 mm has a diameter of 9.017 mm (0.355 in). However, this slight difference in diameter can still create issues when attempting to use one cartridge in a firearm designed for the other.
  • Chamber pressure: Most importantly, the chamber pressure for the .380 ACP is much lower than the 9mm. This results in less recoil for the .380 ACP, so it’s more manageable for smaller handguns and shooters with less experience. However, this also means that the cartridges are not interchangeable.

Potential Dangers and Consequences of Using the Wrong Ammunition

Using the wrong ammunition in your gun can have severe consequences, including damage to your firearm, injury to the shooter, or even death.

Catastrophic Failure

Firing a cartridge in a firearm not designed for that specific cartridge can cause the chamber to rupture. This is called a “catastrophic failure” of the firearm which will likely permanently damage the firearm and may injure or kill you.


Using the wrong ammunition can cause various malfunctions, including: 

  • Failure to feed (FTF): The firearm can’t slide the next round from the magazine into the chamber.
  • Failure to extract: The firearm can’t remove the casing from the chamber after it fires the round.
  • Failure to eject (FTE): Even though the firearm extracts the casing, it can’t eject it. Sometimes this is called a stovepipe, which usually leads to an FTF.

These malfunctions can damage your firearm and risk injury to you or those around you.


Since .380 ACP rounds are smaller and lighter than 9mm rounds, they might not provide the same level of accuracy when fired from a 9mm firearm. The barrel of a 9mm firearm is designed for 9mm projectiles, so even if a 9mm firearm successfully fires a smaller .380 ACP projectile, it will likely have reduced accuracy and performance.

Legal Issues 

In some jurisdictions, using ammunition not specifically designed for your firearm may be illegal. You may face penalties or even the confiscation of your gun. Always check your local laws and follow the manufacturer’s recommendations for ammunition usage.

Alternatives to Using .380 ACP in a 9mm Firearm

Shelves with rifle and pistol ammo boxes at a gun shop

If you find yourself in a situation where you have a 9mm firearm and only .380 ACP ammunition available, consider the following alternatives. 

  • Borrow or buy the correct ammunition from a friend, family member, or gun shop. I’ve always found 9mm ammunition in a pinch since it’s one of the most common cartridges out there.
  • If you have a concealed carry permit, consider carrying a backup firearm chambered in .380 ACP for emergencies.
  • Practice situational awareness and avoid situations where you may need to use your gun until you get appropriate 9mm ammunition.

Final Thoughts

You should not shoot .380 ACP ammunition in a 9mm firearm. It could cause malfunctions, damage to your gun, serious injury, and potential legal issues. To stay safe and well-armed, follow the manufacturer’s ammunition usage guidelines to ensure you use the correct cartridges for your gun.

For more, don’t miss Can You Shoot 6.5 Creedmoor in a 308 Rifle?