380. Vs. 9mm: Do You Know The Difference?

difference between 380 and 9mm

My first recollection of both the .380 and 9mm calibers comes from around the late 1980s. At that time, I had stepped into the adult world and had my sights focused on acquiring my very first self-defense weapon.

My teenage research was thus limited to magazine articles and talking to anyone and everyone I knew who had an interest in firearms, including the owner of the only Gun shop that existed within the 50-mile radius of where I lived. What struck me was how little known the 9mm cartridge was at the time and, by contrast, how popular the .380 was. It was availability which most likely decided the situation at the time. 

Both the 380ACP and 9mm are excellent calibers for their intended purpose. I eventually bought a 9x19mm pistol due to its higher magazine capacity.  I have never regretted the decision but have always had a slight niggle in my mind wondering if I made the right choice.

How Long Have The .380ACP And 9mm Cartridges Been Around?

John Moses Browning is credited with the invention of the .380ACP (9×17.3mm) cartridge in 1908. It was made specifically for use in the then newly released Colt Model 1908 pocket hammerless semi-automatic pistol.  

The 9 x 19mm pre-dated the .380ACP by a few years and was invented by the Austrian firearm designer Georg Luger in 1901 for the 9mm Luger pistol. Both calibers surviving the test of time and still prospering in sales for well over 100 years is astounding and testament to their popularity!

By What Other Names Are The .380ACP And 9mm Known?

As the popularity of the two calibers grew over time, numerous ammunition manufacturers the world over wanted their share of the pie.  Many created identical versions of the original bullets but called them by different names to overcome patent issues of the past. Most of them don’t exist anymore, but they have left us with a few name variations for the same ammunition.

.380 ACP

  • 9mm Short
  • .380 Auto
  • 9mm Browning
  • 9mm Kurtz
  • 9mm Browning Court


  • 9×19 Parabellum
  • 9mm Luger
  • 9mm Parabellum
  • 9mm NATO
380. Vs. 9mm: Do You Know The Difference? 1

Design Specifications .380 Vs 9mm

Detail.380 ACP9x19mm
Case TypeRimless straight walledRimless Tapered
Bullet Diameter.355 in (9.0mm)0.355 in ( 9.01mm)
Land Diameter.348 in (8.8mm)0.347 in (8.8mm)
Neck Diameter.373 in (9.5mm)0.380 in (9.6mm)
Base Diameter.374 in (9.5mm0.391 in (9.9mm)
Rim Thickness.045 in (1.1mm)0.050 in (1.2mm)
Rim Diameter.374 in (9.5mm)0.392 in (9.9mm)
Case Length.680 in (17.3mm)0.754 in (19.1mm)
Overall Length.984 in (25.0mm)1.169 in (29.6mm)
Maximum Pressure21 500 psi (148MPa)34 084 psi (235MPa)

Visually the two calibers, .380 and the 9mm, are very similar. In terms of design, there are significant differences. Specifically, noticeable when looking at the above table is the vast difference in operating pressures. The high pressure at which the 9mm operates permits more energy to be generated, making the caliber better suited to utilizing heavier bullet weights. This pressure results in greater velocity being generated, which in turn gives the 9mm bullet greater momentum.  The higher the momentum, the deeper the bullet’s penetration.    

Velocity Comparison Between The .380 Vs. 9mm

.380 ACP       9mm

Bullet Mass / TypeVelocityEnergyBullet Mass / TypeVelocityEnergy
90 gr Buffalo JHP1025 fps210 ft.lbf115 gr Federal FMJ1180 fps355 ft.lbf
95 gr Federal FMJ980 fps203 ft.lbf124 gr Federal FMJ1150 fps364 ft.lbf
100 gr Buffalo +P HC-FN1160 fps299 ft.lbf124 gr Norma Envy FMJ1345 fps498 ft.lbf
Not Tested115 gr Underwood JHP +P+1400 fps501 ft.lbf
45 gr RBCD TFSP1280 fps309 ft.lbf60 gr RBCD TFSP2010 fps538 ft.lbf

As can be seen from the above table, the average bullet weight used in the 380 compared to the 9mm is approximately 25% lighter. 

Velocity wise the difference is about 15% in favor of the 9mm, and the energy comparison shows a difference of around 20% and more.

This difference is pretty significant in terms of performance, with the 9mm coming out tops in all categories as expected given its design. 

Having said that, the .380 is no slouch. Propelling a bullet at an average speed of just over 1000 feet per second most definitely has the ability to cause a severe wound and even death. To put this into context, a .22LR shoots a roughly 40gr bullet at the same speed and is classed as a high-velocity cartridge. 

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Why Are The 380 And 9mm So Often Compared To Each Other?

The comparison is because, at a glance, the two bullets look pretty much identical. They’re both a 9mm diameter bullet, and both have straight-walled cases.  The only tiny difference is in case length. Fortunately, the design difference is significant enough to avoid the two cartridges being fired in the wrong pistol. This would potentially have disastrous consequences for the .380 given the significant operating pressure difference between the two.

In addition, the .380 and 9mm have both established themselves as reliable and very popular personal protection calibers. They have been used in numerous confrontations where humans were shot. This has led to a lot of debate comparing the effectiveness of these calibers in such situations.

Both the .380 and the 9mm have pros and cons, which merit their existence. Comparing the two calibers is almost an unfair comparison as both are great for their intended purpose. If anything, the .380 is complimented by the fact that it is compared to the 9mm. As we know, the 9mm wins the race, so to speak, when it comes to velocity. The .380, however, makes up for velocity by reliably stepping up to the plate when required to do so. 

Which Caliber Is Better For Self-Defense?

When deciding which caliber is better for self-defense, .380 or 9mm, we have a few factors to consider.

Firstly, .380 caliber Pistols are generally more compact than 9mm pistols. Naturally, this means that it is easier to carry concealed. It is also less of an inconvenience to carry every day as it is less weight to carry around. The pistols profile, in general, is smaller, so less chance of getting in the way of day-to-day activities, and they’d be more concealable. 

The advent of compact 9mm pistols in recent years, combined with polymer materials used so often now in pistol design, has closed the gap in concealed carry between the .380 and 9mm pistols. Carry convenience plays a large part in regularly carrying your weapon and it being there when you need it. In practical situations having virtually any weapon in hand when trouble strikes is infinitely better than having a .50 Cal in the safe at home where it cannot help you.

In terms of ballistic performance, the 9mm comes out on top. This is great in terms of quickly incapacitating an attacker, but as we know, the magical one-shot stop is very rare. In a life or death situation, the aim is to incapacitate the attacker as swiftly as possible. During this highly stressful experience, you would need to deliver as many shots into the vital area of the attacker as required to stop him within the shortest possible time. 

In this situation, firing a pistol that has excessive recoil wastes valuable seconds. It is, therefore, less desirable. The .380, which generates significantly less recoil than the 9mm, has a significant advantage in these invariably close-quarter situations. Practically, the difference between the two calibers’ velocity, especially at a distance of a few feet, would make little difference in the final result.  

As we know, for every action, there’s an equal but opposite reaction. In terms of recoil generated by the two calibers, the .380 is much less.  This makes the pistol notably more manageable and comfortable to shoot. The opposite is true for the now much lighter and smaller 9mm compact and sub-compact pistols that are so popular. Combining a small pistol with a relatively high-velocity cartridge invariably generates more recoil. This added recoil can be downright painful to the shooter and may, in fact, induce a flinch.   

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What Does It Mean To Flinch?

Flinching can be described as a subconscious self-protection reaction triggered by the noise generated by the pistols muzzle blast and the weapon’s recoil. Flinching reduces the shooter’s ability to place shots accurately on target. The flinching reaction is physically expressed through the following reactions at the instant when the shot is fired:

  • Subtle to very obvious forward lunging of the torso
  • Forward and downward push or dipping of the weapon’s muzzle in an attempt to resist the recoil
  • Closing of the eyes at the shot
  • A step forward after the shot
  • Consistently shooting low on the target
  • Rushing the shot to get it over with
  • Yanking the trigger instead of squeezing
  • Not using the weapon’s sights as intended
  • No follow-through after the shot

In some cases, the poor fit of the pistol in the shooter’s hands makes trigger control very difficult. A weapon that is too heavy or too small for the person shooting can make the shooting experience unpleasant. People enjoy doing things in which they can excel. 

The major factors causing flinching can be quickly addressed by correcting one’s shooting stance, wearing quality ear and eye protection, being made aware of the issues observed, and learning to accept the recoil and how to deal with it. All, of course, to bring enjoyment back into the shooting experience by improving your shooting ability.

Which is more accurate: .380 Or 9mm?

Many factors affect the accuracy of a caliber. None more so than the shooting ability of the shooter. Shooting at a dedicated target, given ample time and accuracy being the only objective, the .380 and 9mm will perform toe to toe. 

Given an exercise where both speed and accuracy are the measurable aims, the .380 will almost always come out on top. The reason for this is the lower recoil developed by the .380 caliber. Less recoil equates to faster recovery time and faster follow-up shots. The 9mm generates more recoil than the .380, which is a disadvantage where speed is the aim.  

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Ammunition Choice For The .380 And 9mm 

The shooting world has never had it as good as we have it now in terms of choices available and technological advancements in bullet technology. This is good news for especially the .380 and 9mm supporters. Bullet choice can go a long way to improving the terminal performance of your chosen caliber. 

Bullet offerings like the new Black Hills spiral Fluted HoneyBadger ammunition have improved the performance of previously borderline self-defense calibers into truly reliable ammunition. The .380 arguably benefits more out of these developments than the 9mm. Nonetheless, both calibers are highly effective.

Bullet choice was an important factor to consider in the past. This is because the majority of the smaller framed pistols sacrificed magazine capacity to achieve their compact size. Advances in weapon design have increased the compact and sub-compact weapons magazine’s ability to be on par with their bigger cousins. This development brings the .380 caliber sub-compact pistols into the same league as the high capacity 9mm type pistols, making them serious contenders in the self-defense world.    


When comparing the .380 and 9mm calibers, the physical design elements of the two cartridges are very similar. The 9mm undoubtedly has the edge in terms of downrange performance, which unfortunately comes at the cost of added recoil, muzzle blast, and generally a more robustly built weapon. The .380 makes up for its slight ballistic shortfall by being more practical in general as a concealed carry gun. Reduced muzzle blast and recoil are a distinct advantage when fast, accurately placed follow-up shots are required. 

Being so similar in performance and design, the only real advantage that the 9mm has over the .380 is the higher velocity. Both the .380 and the 9mm have a well-established following in the shooting fraternity. Choosing which caliber would best suit your needs would come down to personal preference. Personally, I can’t wait to add a .380 to my 9mm.