38 special ammo vs 9mm – Which Is Better?

Mid-bore Handgun Ammunition – .38 Special Ammo vs 9mm Ammo

With so many different handgun and ammunition options on the market, it’s overwhelming and difficult to determine what caliber is best suited for you. Frankly, a lot of that will depend on what type of shooting you intend to be doing. I’ll take you through some of the finer points of the differences between two popular calibers: the .38 Special and the 9mm.

Comparison Criteria
.38 Special
Weapons PlatformMostly used for revolversWide range of platforms (semi automatic pistols, fully automatic sub machine guns, and several carbines)
Physical CharacteristicsCartridge - Rimmed, centerfire cartridge
Diameter - 0.357 inches
Cartridge - Rimless, tapered cartridge.
Diameter - 0.355 inches
Muzzle velocity900 feet per second1110 feet per second
Drop at 100 yards14.9 inches9.8 inches
Maximum Pressure35000 psi17000 psi

Weapons Platforms

First things first, the biggest difference between these two types of ammunition are the weapons that are chambered for them.

The .38 Special is almost exclusively limited to revolvers. The snub-nosed Chief’s Special has a storied history that dates back to shortly after World War II, and not very much has changed since then. There are some other options that are chambered for .38 Special like Marlin or Winchester lever action rifles, but they are few and far between. Although post-World War II is when a marked increase in popularity occurred, the .38 Special round was actually developed in the 1890s, and I’ll explain why that’s important shortly.

On the other hand, the 9mm round is used in semi automatic pistols, fully automatic sub machine guns, and several carbines. There are even a number of modern revolver manufacturers that are now offering their wares chambered in 9mm like Taurus, Charter Arms, and Smith & Wesson.

Physical Characteristics

If you take a look at the physical dimensions of .38 Special ammo vs 9mm ammo, you will find that they are extremely similar except for their length. They both have a virtually identical diameter with 9mm measuring 0.355 inches and the .38 Special coming in at 0.357 inches. The 9mm casing is three-eights of an inch shorter than the .38 Special, and the .38 Special had a slightly larger rim on the casing to accommodate seating in a revolver.

The reason for the longer casing is due to the ammo’s original design using black powder as the propellant. At the time of its creation in 1898, the .38 Special was intended to replace the .38 Long Colt round as it was proving ineffective for military application. The additional room allowed for more powder to over pressurize the round and create higher exit velocity and impact force despite the inefficiency of black powder as a propellant. Just a few years later in 1901, smokeless powder had replaced black powder as the propellant of choice in ammunition, and much smaller loads were needed to generate equivalent force hence the shorter casing of the 9mm.

If the 0.357 inch diameter looks familiar, then you picked up on another unique distinction with the .38 Special ammo. They can be fired from the majority of weapons chambered for .357 Magnum loads, but the reverse is not true. The much greater barrel pressure of the Magnum load is far too high for .38 Special chambered weapons to handle without significant modification.

Is Cost a Factor?

Moderately priced weapons for both calibers are available, but the true continuing cost is going to be from the ammo itself. A quick search will show you that 9mm ammo currently averages around 25-40 cents less per round than .38 Special ammo for decent ammunition. That may not seem like much at face value, but at case prices, you’re now paying $250-$400 extra. It’s important to remember that ammunition price fluctuates with availability and the market, but generally speaking, 9mm is going to be cheaper than .38 Special for quality ammo.

I don’t recommend putting box after box of cheap ammo through your gun either. Cheap ammo runs dirty, and dirty weapons malfunction. If you’re relying on your weapon for concealed carry purposes, then you absolutely can’t count on bottom of the barrel ammo. Even if you’re doing recreational shooting, do you really want to clear a malfunction every 10 minutes? Revolvers are not immune from malfunctions either even with their reputation for reliability, and dirty ammo is the quickest way to cause most of them.

Inherent Accuracy

When I talk about accuracy, it’s more referencing bullet drop over distance. Outside of that factor and a properly sighted weapon, the shooter is the largest contributor towards accuracy. Sight alignment, sight picture, grip, stance, and trigger pull are all going to have a far greater effect on overall accuracy than anything to do with ammo caliber. That being said, this is an area where the 9mm far outshines the .38 Special, and I feel it’s worth spending some time on.

Like all of ballistics, bullet drop is simple physics. Muzzle velocity and projectile weight directly correlate to bullet drop. Higher muzzle velocity and a lighter projectile lead to less drop, and if you increase projectile weight or decrease muzzle velocity, you will see a steep increase in bullet drop. This is where that higher internal pressure in the 9mm that I mentioned earlier comes into play.

With an equally weighted bullet at 124 grain, the .38 Special has a muzzle velocity of 900 feet per second compared to the 9mm at 1,110 fps. At 100 yards, that drops to a velocity of 817 fps for the .38 Special and 971 fps for the 9mm. Also at 100 yards, the .38 Special bullet will drop 14.9 inches, but the 9mm only drops 9.8 inches. Realistically, no one is taking 100 yard pistol shots in a gunfight, but this distance clearly illustrates the significance of the difference between the two loads.

Stopping Power

The most efficient way to stop a threat is to put effective rounds on target. Vital organs and the spinal column are the keys to stopping a lethal threat, but the energy behind a round can assist in other ways as well. 9mm casings are reinforced to handle nearly double the pressure rating as .38 Special casings. With the 9mm at 35,000 PSI or 38,000 PSI for +P loads, it is a substantial difference compared to the .38 Special at 17,000 PSI up to 20,000 PSI for +P.

Looking at similar weighted rounds from Federal Ammunition, the 9mm Hydrashok round at 124 grain generates 345 foot pounds of force at the muzzle while a 129 grain Hydrashok +P .38 Special round generates only 258 foot pounds at the muzzle. That’s nearly 100 foot pounds of difference even giving the .38 Special ammo the added benefit of an over pressurized +P load and a heavier projectile.


The FBI sets a standard of penetration between 12-18 inches for a reason. That distance is reasonably likely to result in stopping power by impacting critical internal organs but without the risks associated with over penetration. I would be remiss by not pointing out that both of these calibers have numerous ammo loads that fall within that effective range, and both the .38 Special and the 9mm are quality self defense calibers. That being said, this is a comparison, and in equivalent loads the 9mm rounds penetrate further into that effective range than their comparative .38 Special rounds by an average of 1.5 to 2 inches. Even the lightest loads in 9mm will reach the 12 inch FBI minimum, and the same is not true for the .38 Special.

Recoil Considerations

You might think that the high-pressure 9mm ammo would generate much greater recoil, and you would be technically correct if we were talking about recoil in a vacuum. Perceived recoil is much more important as that is what is directly experienced by the shooter. Energy from the round is critical, but other factors contributing to perceived recoil include:

  • Bullet weight
  • Weapon platform
  • Slide weight
  • Grip fit

In a straight comparison between a .38 Special revolver and a 9mm revolver, the perceived recoil would be much greater in the 9mm. You would also experience increased muzzle lift and a more difficult recoil management process overall which would hamper accuracy on follow up shots. Thankfully, 9mm revolvers are few and far between, and they are of greater interest to revolver aficionados than someone looking for a concealed carry weapon. The design of a semi-automatic pistol is purposely built to redirect recoil and use it to chamber the next round. This results in significantly less perceived recoil when compared to a revolver even with the much higher energy levels of the ammunition.

Final Verdict – .38 Special Ammo vs 9mm Ammo

If you are someone who exclusively wants a revolver for concealed carry, then I don’t think you could make a better choice than a .38 Special. They are compact, reliable and an even trade off between concealment and stopping power.

For virtually any other type of shooting, I would go with a semi automatic pistol chambered in 9mm when forced to choose between the two. If you are not dead set on a revolver for concealed carry, then I truly believe that a 9mm semi auto handgun is the overall better choice for concealed carry as well. The higher internal pressure translates into greater velocity, increased stopping power, better accuracy, and more expansion. That’s without even addressing the benefit of a magazine holding 18 rounds which would require three reloads of a five shot .38 Special revolver to put equivalent rounds down range.

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