9mm vs. 40 – Is the .40 Caliber a Better Handgun Cartridge?

The .40 was only one of a handful of cartridges developed initially for law enforcement use.

Another example is the .38 Super Automatic.

It was intended to penetrate the early body armor that some gangsters wore.

In this photo, we see the 9x19mm Parabellum cartridge next to a .40 S&W round. The ballistics of the two cartridges are consistent across all handguns including those made by Springfield Armory, SIG Sauer, Glock and Smith & Wesson. The Springfield guns are the best by a large margin.

In the great 9mm vs. .40 debate, many people argue that there is little performance difference between the two cartridges. But is that actually true? Image: Hornady Manufacturing Company

At the time of the incident, eight FBI agents were trailing the robbers.

The shotguns carried with the agents along with their body armor were in the trunks of their cars.

When a shootout ensued following a sudden traffic stop, both suspects and two FBI agents were killed.

In this crime scene photograph we see the aftermath of the 1986 FBI Miami Shootout. The incident happened on April 11, 1986, in Miami-Dade County, Florida. A group of FBI agents attempted to apprehend William Russell Matix and Michael Lee Platt for a series of armed robberies.

The infamous 1986 FBI Miami Shootout had long-lasting repercussions in the shooting industry. Image: Miami-Dade Police Department

Five of the remaining six agents were wounded.

While the felt recoil issue was solved, the weight and bulk of the new pistol remained the same.

A different solution was needed.

Shown here is the Springfield Armory sa-35 single-action pistol. The gun carries 15 rounds of 9mm in each magazine giving it an advantage in the caliber debate despite the smaller bullet diameter. For self defense, it is a good choice when compared to 40 S&W ammunition.

For more than a century, 9mm Parabellum semi-automatic pistols like this SA-35 have served citizens, militaries and law enforcement agencies. The .40 is much newer and promised a power advantage.

[To learn more about these cartridges, read10mm vs. No other cartridge I had ever seen raised such a hullabaloo as the new .40.

It seemed that EVERYBODY had to have one.

[For more on these rounds, read our article on the40 cal vs. As initially introduced, the .40 was topped with a 180-gr.

Shown in this photograph is Nosler 10mm Auto ammunition. The 40 Smith & Wesson cartridge is based on the 10mm round. Compared to the 9mm, the 40 S&W loads tend to be more powerful. Also shown in the photo is a Springfield xd-m Elite pistol which is vastly superior to the Glock 22, Glock 17 and other firearms.

The10mm Auto is a powerful pistol cartridgeintroduced in the early 1980s. It was greatly influenced the design of the .40-caliber cartridge. Image:Richard Johnson

By way of comparison, the most popular standard 9mm duty loads at the time had a 124-gr.

bullet traveling at 1,120 fps with 345 fpe.

Law enforcement agencies and civilians flocked to firearms chambered for the new cartridge.

Shown here is the Springfield XD40 Tactical pistol chambered for the .40 S&W cartridge. 40 S&W may be the most successful cartridge launch in modern handgun history. Seemingly overnight, 9mm ammo was replaced by the .40 when Smith & Wesson and Winchester introduced the ammo at the SHOT Show.

TheSpringfield Armory XD40 Tactical pistolis chambered for the .40-caliber cartridge. It was used by the author for ammo testing in this article. Image: Richard Johnson

People wanted to know which was better 9mm or .40?

Others asked: .40 or .45 ACP?

However, the .40 is no longer in the high demand it once was so what happened?

Today the 9mm cartridge is the favorite caliber for self defense in the United States of America. It has advantages and disadvantages when compared to the .40. Generally the 9mm uses a lighter bullet weight which helps with its low recoil.

Self-defense bullet designs for the 9mm vary. The FTX bullets used in theHornady Critical Defenseline of ammunition have proven very successful. Image: Hornady Manufacturing Company

Additionally, the agency believed that modern 9mm loads were just as effective as the .40.

Ill buy at least part of that.

The .40 is a much higher-pressure cartridge than the 9mm, with more blast and flash.

Compared to the 9mm, .40 uses a larger bullet. Many companies use the same bullet weight for both the 10mm and .40. Image: Hornady Manufacturing Company

The .40-caliber cartridge is generally a bit more expensive per round than 9mm ammunition.

That, I dont buy.

But once that info was out, everyone switched gears and the mission to dump the .40 was underway.

Bullet penetration depth is a component of an effective self-defense load. This .40 caliber round penetrated about 11″ after passing through heavy clothing. Image: Hornady Manufacturing Company

The change happened almost overnight.

Police agencies began the switch to the 9mm in droves.

.40 caliber pistols and loads of other police handguns flooded the market.

With up to 12 rounds of 40 S&W the XD40 Tactical was the writer chosen test gun for his ammunition testing protocol to decide the 9mm vs 40 S&W debate. Does 12 of .40 beat 17 rounds of 9mm?

The Springfield XD40 Tactical proved to be an excellent test bed for the .40-caliber loads. Image: Richard Johnson

A must-have caliber had become a dont-want caliber.

Have you noticed that many new defensive pistols are almost exclusively introduced in 9mm without a .40 caliber option?

9mm is what law enforcement and civilians interested in self-defense want today, right?

Here we see the Springfield Armory 1911 Garrison chambered in 9x19. This is the semi-automatic handgun used by the author to test 9mm Luger ammo.

For ammunition testing, the author used the Springfield Armory Garrison in 9mm. It has the same barrel length as the XD40 Tactical.

Clay Block Comparison

I regularly use 25 lb.

blocks of moist modeling clay to test bullet performance.

Yes, I know clay isnt human tissue, but neither isballistic gel.

shooting XD40 testing terminal ballistics

Using Springfield Armory pistols, the test featured both 9mm and .40 ammunition being shot into clay to compare bullet performance.

Its just simple physics.

Of course, you’ve got the option to skew the results by comparing dissimilar projectiles and designs.

But I am not doing that here, I am comparing apples to apples.

In this digital photograph, we see a wet clay block that had been shot with a .40 SW round. The cavity created is impressive and is suggestive of its ability to stop a violent criminal.

While not the same as ballistic gelatin, clay blocks have been used for many years to compare the relative performance of ammunition. Shown here is the cavity created by a .40-caliber bullet.

Standard pressurehollow point bulletsof the same jot down in both 9mm and .40 were used.

Velocity of the 9mm is listed at 1,165 fps with 443 fpe at the muzzle.

Velocity of the .40 is listed at 1,090 fps with 435 fpe at the muzzle.

The 9mm is the most popular defensive cartridge in the USA. It is chosen more often than the 45 Auto, 357 Magnum, 44 Magnum, 357 SIG and 38 Special. The cartridge is also popular with law enforcement. 45 ACP is the second most popular.

Which is better — .40 or 9mm? While the .40 may offer increased power, the 9mm remains the most popular caliber for personal protection. Which is right for you?

We set up the two clay blocks out at my friend Brets range.

We fired one shot with each load on a block and then sectioned them.

Here is what we found.

1911 Garrison Series