When the FBI ditched 9mm, and then 10mm

The Federal Bureau of Investigation, FBI, has constantly tested the limits of ammunition and new guns for more than 100 years.

If the FBI use your shit, it’s good shit. That endorsement helps companies selll thousands of Glocks, Smith & Wesson M&P Sport rifles and more sophisticated wares. Conversely, if the FBI publiclfalls out of love with your product, that can have a seriously negative impact.

So it was in 1986 when the failure of 9mm to bring down yet another suspect in a now famous shootout in Dade, Florida, proved too much. Having decided the basic body armor all too many criminals had access to was enough to defeat 9mm, the agency decided to switch up to a more powerful round.

They chose the 10mm Auto, which is a powerful round that can penetrate body armor. The FBI used the 10mm Auto for several years, but was never truly convinced.

Pros & Cons of 10mm Ammo

Now we love the 10mm Auto, in its proper place. And now you can get 10mm concealed carry guns that just about do the job, but this is really a favorite bear defense gun if you’re in the rocky wilds of Alaska.

As home defense guns, a full size 10mm pistol that can tame the recoil that goes with the more powerful cartridge is a beautiful thing.

You can check out the best 10mm pistols here:

As a general purpose handgun, though, and especially as a defensive handgun load, the 10mm Auto has serious issues.

Recoil is a Problem

First, the 10mm Auto is a more powerful round, but it also has more recoil.

This can make it difficult for some agents to control, especially when they are firing multiple rounds in rapid succession.

Now that’s the polite way of saying most agents sucked with the 10mm Auto. The Colt Delta Elite and Smith & Wesson 1076 were the main options.

Some agents simply couldn’t get a good grip on these massive handguns. They were just too big for agents with smaller hands.

Accuracy went down across the board. And it doesn’t matter if the round is more powerful if you’re just not hitting the target as often. We know now that shot placement is way more important than power or even the caliber. That was a lesson the FBi had to learn the hard way.

The FBI Firearms Training Unit eventually concluded that 10mm recoil was just too much for the average agent and reserved 10mm for the highly trained Hostage Rescue Team and elite tactical teams.

Concealment Also a Big Problem

The big 1911s were also hard to conceal and also harder to draw to engage in the first place. In a gunfight, they held way less rounds than a smaller 9mm compact handgun.

That did get better over the years with the Glock G29 sub compact 10mm handgun aimed solely at CCW, and more recently the Springfield Armory XD-M Elite Compact OSP with its 3.8 inch barrel.

So 10mm would be a viable option now, but back in the 90s the agency started looking for another alternative.

In 1990 a new cartridge launched and entered the testing pool. By 1997, the agency decided that 40 S&W was the answer.

When did the FBI Switch to 40 S&W?

In 1997, the FBI moved to 40 S&W and the Glock 22 and Glock 23 became the standard issue firearms.

This new caliber was seen as the perfect compromise. It was more effective against body armor, but not quite as violent as 10mm when it came to the recoil, or 45 ACP for that matter.

So the FBI switched to 40 S&W, and a massive number of Law Enforcement Agencies followed suit. Like we said, that FBI endorsement is a big deal.

How did We Get Back to 9mm?

The 9mm has improved significantly in recent years. Newer 9mm rounds are more powerful and more effective than the rounds that were used in the Miami shootout. As a result, the FBI now believes that the 9mm is a sufficient caliber for their needs.

In 2015, the FBI announced that they would be switching back to the 9mm. They chose the Glock 19, which is a popular 9mm pistol. The FBI also adopted a new type of 9mm round, the Speer Gold Dot G2. This round is designed to expand rapidly upon impact, which increases its stopping power.

The advance in hollow point bullets was one of the main reasons the FBI could return to a the more manageable 9mm Luger round. Now, after decades of experimentation, the FBI came to the same conclusion as the market, 9mm is the self defense king.


  • Nick Hall

    Nick is a lifelong gun enthusiast who has a simple mission. He wants to find the best deals for guns online and help you make the best choices with weapons your life may depend on one day.Nick won a minor league shooting competition at the age of 11 and it all went from there. Now he runs one of the biggest firearms websites on the net and his work has featured in Playboy US, Tatler Asia, Forbes and a whole host of national magazines and websites.

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