Guest post written by Suzi Shooter

Springfield Armory just announced the release of two new (apparently) highly-anticipated pistols—a 4.5-inch and 5.25-inch XD(M) chambered in 10mm. Springfield claims, as well as fans on the internet say, customers have been begging for this gun for years. The 10mm isn’t necessarily a popular round, but it certainly has a cult-like following with its fanboys. This powerful round has had its ups and downs in its 35-year history, but one thing’s for sure—it clearly isn’t going anywhere any time soon.

FirearmBlog reader comments on the new Springfield XD(M) 10mm: "This is the only announced new gun that I have cared about for the last couple years."

We all know and have probably, even if by accident, gotten ourselves wrapped into a .45 ACP vs. 9mm debate. There’s always a few who chime in that neither will do, .40 S&W’s the best (no argument there) and then there are the guys who like to throw their weight around and insist that 10mm is the only REAL man’s caliber.

Now, I’m a woman and my daily carry is a .380 ACP. Though I have shot nearly every handgun caliber, I have honestly never shot a 10mm. I’m just not a big fan of the mine-is-bigger-than-yours calibers for concealed carry…but anyway, I digress… My point is, the 10mm isn’t the only serious and legit choice for self-defense. Now, back to business.

Much has been written about the 10mm, probably because it’s an elusive round, yet immensely popular with loyalists. One of the reasons why people are so curious about it is due to its history.

The 10mm cartridge outperforms the .40 S&W
The 10mm

One common story widely believed is that the 10mm was designed in response to the 1986 FBI Miami Shootout between 8 FBI agents and 2 bank robbers where FBI agents were under gunned. The truth is, the 10mm was already in the works. The late grandfather of self-defense pistol techniques, Lt. Col. Jeff Cooper, had already been experimenting with wildcat rounds trying to create a caliber hotter than the .45 ACP.

You see, back in the day, bullet technology wasn’t like it is now and larger bullets, not necessarily bullets with the most energy, were preferred for their “knock down power.” Handgun shooters felt like 9mm was too small and that .45 ACP was too slow to be wholly effective in stopping a bad guy.

Jeff Cooper was a huge fan of the 1911 and the .45 ACP and felt that semiauto shooters should have a caliber that equaled magnum revolver cartridges. Sometime in the 1970s, he started playing around with different cases and bullets to see if he could create a successful new round that met those requirements.

Around the same time, two firearm designers, Thomas Dornaus and Michael Dixon, were thinking the same thing. In the early weeks of 1980, the two went to visit Jeff Cooper and asked him for his counsel in helping them design a new semiautomatic firearm that would hold more rounds, reload faster and be more powerful than the .45 ACP and .357 Magnum.

Jeff already had a round he thought would be perfect for this gun. He called it the .40 Super. The .40 Super—a .30 Remington case with a .38-40 .400-inch diameter bullet—a round that achieved 30 percent more energy than a .45 ACP. This new round flew flatter and further than the .45.

Dornaus and Dixon incorporated in 1981 and developed the 10mm Bren Ten (influenced by the CZ-75) pistol. Norma made the ammo. The Bren Ten quickly gained popularity after becoming Sonny Crockett’s pistol in the series Miami Vice. However, Dornuas and Dixon closed its doors in 1986.

In the same year the Bren Ten production ceased, a tragic event forever changed law enforcement and in turn, the gun world.

Sonny Crockett, a character on the 1980s hit Miami Vice carried a 10mm Bren Ten.
The Bren Ten was only produced for three years.

On April 11, 1986, armed with a 12-gauge shotgun, .357 Mangum revolver and a .223 Ruger Mini-14 rifle, two bank robbers, William Matix and Michael Platt engaged in a five-minute shootout with eight FBI agents. Two FBI special agents died during the shootout—Jerry Dove and Ben Grogan. Five others were hurt. Both bank robbers were hit multiple times—Matix was shot six times and Platt 12—but both were able to continue fighting before finally falling.

This shootout was the catalyst for the FBI to begin searching for a bigger caliber. During the analysis of the shootout, the FBI found that one of the 9mm rounds Special Agent Jerry Dove fired hit Platt in the arm, went through his chest, but stopped just short of his heart.

During the time, everyone focused on the expansion of a bullet, not penetration. Impressed with the ballistics, the FBI chose the 10mm, which was a very short-lived decision.

Since the 10mm was a very new cartridge, there weren’t many firearms chambered for it. When the FBI chose the 10mm as its new service round, Smith & Wesson stepped up to the plate with the 1076; however, because of the rush, the 1076 had some serious problems and malfunctioned a lot. Jacki Billings on writes, “The FBI ordered 10,000 Smith & Wesson 1076 pistols but only accepted 2,400 before canceling the contract due to parts breaking during routine training and qualifying.” Besides that, there were many FBI agents unable to pass their shooting tests due to the recoil of the 10mm. (It’s important to remember here that just because one is in law enforcement, doesn’t make one a gun person.)

The failure of the 10mm for duty lead to the invention and adoption of the .40 S&W, as well as the FBI ballistics tests, which are still held today as the definitive guide to ballistics. From the NRA’s Shooting Illustrated:

Experimentation at the FBI’s Firearms Training Unit soon discovered that they could achieve the terminal ballistics results they sought with the same bullet moving a couple hundred feet slower. With less powder required, less case was required to hold it, and thus was born the .40 S&W and thus (mostly) died 10mm Auto’s stint as a law enforcement cartridge.

Today, quite a few major manufacturers make a 10mm pistol includes GLOCK, Colt and SIG Sauer. Further, the 10mm has also earned its place as a hunter’s sidearm against bears, deer and even elk.

There Truly is No One Round to Rule Them All

The 10mm has its fans and for legitimate reasons. It’s a cartridge developed to stop a threat and has consistently come up on top for ballistics on the FBI’s ammo tests. As far as it being the best mm, I’m not here to argue that. The 10mm has a rightful place at the table, but so does the 9mm, .38, .380 and .40. Carry what you shoot most accurately and ask those who think you’re a girlyman because of it if you can go ahead and shoot ‘em with your “wussy” caliber.

What do you think about the 10mm? Tell me below.

3 thoughts on “The On-Again Off-Again Love Affair with the 10mm

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