Can You Fire a 380 in a 9mm Handgun?

9mm and .380 ACP, two powerful handgun calibers widely used by various guns. 9mm is the most common pistol ammunition of all time. There is a reason why people ask if you can fire a .380 ACP in a 9mm handgun. The funny thing is, a lot of people who have no idea about the details of them think they are the same thing just different shells. The truth is quite far from that.

Let’s break some outdoor myths and try to find out the real truth, shall we?

Before we begin, let’s learn a bit about both of this caliber. Try to find out why people compare these two.

.380 ACP

Back in 1908, this century-old pistol ammo was created by Colt for their automatic Colt pistols. John Browning made this legendary ammunition. Even now, a lot of modern gun runs on this ammunition.

Why is that?

Well, it’s a lightweight 9x17mm ammunition that is used for self-defense and security enforcement handguns. It’s made in mass and always available.

Based on .38 ACP which was a bit more powerful, .380 ACP was meant to be truly rimless. Having headspaces on the case mouth instead of the rim to improve accuracy. And that worked. It was indeed packing a speedy punch with better accuracy.

9mm

Even someone who has never held a gun before has heard of 9mm. Used by NATO and others, 9mm is also widely available in plenty of video games. A lot of our youngsters learned about this ammo from games.

Designed by Georg Luger back in 1901, 9mm went into production in 1902. Since then, it’s still in production and being used by NATO and other military-related equipment.

It’s mostly used in handguns but a lot of rifles and SMGs have adapted to use 9mm over the years. This century-old ammo was designed to be rimless for better accuracy. Also known as 9x19mm Parabellum, it is patented under 7.65x21mm Parabellum.

.380 ACP vs 9mm

Specs	.380 ACP	9mm
Size	.380 ACP	9mm
Neck Diameter	.373 in (9.5mm)	0.380 in (9.65mm)
Base Diameter	.374 (9.5mm)	0.391 in (9.93mm)
Rim Diameter	.374 in (9.5mm)	0.392 in (9.96mm)
Case Length	.680 in (17.3mm)	0.754 in (19.15mm)
Overall Length	.984 in (25.0mm)	1.169 in (29.69mm)
Velocity	1050 FPS	950-1400 FPS
Type Cartridge	Pistol Cartridge	Pistol/revolver/carbine/SMG
Penetration	9’	13’
Produced	1908-present	1902-present

As you can see from the specification chart, both of them share a lot of similarities. Besides having some crucial differences like the overall length, they are practically the same. Or are they?

So, the question remains,

Can you use .380 ACP on a 9mm gun?

The answer

The answer is yes, you can use it. But should you? Not.

Well, that sounded harsh. Let me rephrase that in detail why you shouldn’t use .380 ACP on a 9mm handgun.

While both of them share a lot of similarities from the same rimless design to almost the same diameter, a 9mm tube is simply not made to fire an ACP.

While you can fire a .380 ACP through the 9mm barrel, you shouldn’t. .380 ACP simply won’t be able to generate as much pressure as a 9mm would. Resulting in not enough force to make the 9mm slide work.

What that means is that 9mm will malfunction. You will notice on gun ranges or police ranges they mix 9mm with .380 ACP. The reason behind them is quite simple actually. They are swapped places to make officers learn to clear jams and stovepipes without hesitation. This comes in super handy when you are in an emergency shooting situation.

Now on to more why you shouldn’t swap places.

Depending on the gun you are using, the cartridge will either end up 1mm farther than it should and leave the primer out of reach from the firing pin. Or the extractor will hold the cartridge by the breech face. Which might allow you to fire but will cause you to miss the shot. Will have a horrible accuracy as well. It won’t have enough recoil to properly cycle the gun either.

I can understand why you would want to use a .380 ACP in a 9mm gun. I mean, it’s a fun project. Who wouldn’t want to experiment a bit, right? But if the experiment costs you the gun and makes the firing chamber malfunction, is it worth it to you? I certainly wouldn’t call it worth it.

.380 ACP costs more. Another reason why you shouldn’t go around putting the wrong ammo in the wrong gun. 9mm has a high supply where.380 ACP doesn’t. Resulting in a big gap in price between the two.

9mm is more powerful

9mm has a maximum velocity of 1400 FPS where .380 ACP is capped at 1050 FPS. This difference between the two is quite noticeable.

.380 ACP is more accurate

.380 ACP fires with lesser force. Making it more accurate. Sure, it has a shorter range of accuracy. But in a particular rapid-fire situation, .380 ACP will always be ahead of 9mm in terms of accuracy. In terms of single shooting on a long range, well it will mostly be based on how good are you with the gun.

Recoil

9mm punches a bit harder than .380 ACP. Being the shorter of the two, .380 has less recoil. This is also why you shouldn’t even attempt to run a .380 in a 9mm gun.

Conclusion

While it may sound cool in your head and may even be doable. That doesn’t mean you should. There are many things in life better left untouched. This is one of them. Don’t bother with this experiment unless you can afford to spare a gun that might die on you.

In my book, it’s not worth experimenting. But hey, if you want to, who am I to stop you? Ha-ha! Hopefully, this answered your question and was able to satisfy your thirst and fill you with knowledge. Learning about ammunition will give you a technical edge over your competitors.

You are also welcome to save your gun.