The Case for the 10mm for Self-Defense

By Suzanne Wiley

Have we been discounting what could possibly be the best defensive semiauto caliber on the planet?

“To a proficient law enforcement officer whose primary and often only weapon is a pistol, the 10mm Auto is the best choice.” -Guns & Ammo

Jeff Cooper, legendary self-defense pistol instructor was a huge fan of the .45 ACP yet developed the 10mm because of his desire for a better combat fighting round.
Jeff Cooper was a huge proponent of the .45 ACP.

The late Lieutenant Colonel John Dean “Jeff” Cooper, one of the leading pioneers in self-defense pistol techniques, was an avid advocate of the .45 ACP 1911. Jeff Cooper created the Weaver stance and was one of the first instructors to establish the four golden rules of firearm safety. His methods and ideologies are still highly respected today and so, it is difficult to argue his choice in the .45 for self-defense—especially with the proven ballistics behind it. Yet, even Cooper knew the round’s limitation. Though the .45 has proven stopping power, it is a slow-moving bullet—relatively speaking.

Jeff Cooper believed that a better semiautomatic pistol combat round could be developed—one that kept its energy at longer distances. So, Cooper, along with John Adams, Whit Collins and Irving Stone designed the 10mm from a shortened .30 Remington rifle case and put a .40-inch bullet on it. The original 10mm has a 170-grain Jacketed hollow point bullet with 600 ft. lbs. of energy, 1,300 fps and a pressure of 44,440 psi—enough energy to remove the bluing off any pistol! (Gun Digest) The 10mm bullet is smaller than the .45’s, so more ammo fits in the same size magazine. Also, the 10mm Auto goes faster, has more energy on impact and flies further with a flatter trajectory. At the time, there was no other handgun caliber that rivaled the 10mm’s ballistic performance. In fact, the 10mm’s impressive performance rivals that of rifle calibers.

Sonny Crockett's Bren Ten
Sonny Crockett’s Bren Ten

The 10mm was introduced at an optimum time in 1983 when there weren’t many choices in self-defense semiautomatic handgun calibers. Law enforcement were skeptical of 9mm and guns chambered in .45 ACP were full-sized, bulky and not very practical to carry. After developing the 10mm, Cooper needed a gun chambered for it. Dornaus and Dixon stepped up to the plate and introduced the Bren Ten, a semiautomatic pistol loosely based on the CZ 75. Even though the TV show Miami Vice picked up the Bren Ten, in real life it reportedly had issues and magazines weren’t cheap. The Bren Ten was produced for only three years before the company went out of business. Fortunately, Colt released the 10mm Delta Elite, GLOCK introduced the 20 in 1990 and Smith & Wesson made the 1006—most likely saving the 10mm.

The 10mm has the best ballistics performance of any other semiautomatic pistol round.
The 10mm

The 10mm’s second chance came in 1986 after the FBI was underpowered in a shootout with two bank robbers.

On April 11, 1986, in Miami, Florida, Michael Platt and William Maxtix, armed with a 12-gauge shotgun, a Ruger Mini-14 .223 and two .357 Magnum revolvers shot and killed two and hurt an additional five, FBI agents, spurring the agency’s choice to search for a new, more powerful caliber.

Passing the FBI’s tests with flying colors, the 10mm Norma-made 170-grain jacketed hollow point with 1,358 fps lead the tests in best “wound value” and so the FBI adopted it. Embracing it, though, was a different story. The FBI found that some agents couldn’t handle the recoil of the 10mm, and had difficulty being accurate on follow-up shots. The NRA’s Shooting Illustrated points out that in the FBI’s testing report is this statement: “CAUTION: Velocities, pressures and recoil are extreme, vary greatly, and damage weapons with extended use. Control for multiple shots extremely difficult.”

The 10mm vs. 9mm photo comparison
The 10mm on the left and the 9mm on the right

To deal with the problem, the FBI developed a reduced power load to lower the recoil. Called the 10mm Lite, this new 10mm variant didn’t have the same impressive ballistics—voiding Jeff Cooper’s concept altogether.

Then Smith & Wesson made the .40 S&W and the 10mm was all but forgotten.

In recent years, the 10mm has been making a comeback. Handgun hunters realize its full potential. For medium to even larger game, it is, hands down, a winner. As one of the few pistol rounds legal to hunt deer, 10mm takes down deer, hogs and even bear quickly.

What the 10mm doesn’t have going for it is its availability and cost. It’s still “rare” and there aren’t that many firearms chambered for it, especially ones easily concealed. But for a round that outperforms the .45 ACP, .357 Magnum and the .40 S&W, it is a wonder we don’t see it used more commonly.

The gun industry, like all others, ebbs and flows with trends. A few years ago, it was subcompact .380 pocket pistols, soon after, it was 9mm in those same guns. If we’re all looking for the best stopping power in a gun that is lightweight, easy to shoot and comfortable to carry, gun manufacturers should give the 10mm serious consideration.

What do you think about the 10mm? Tell us in the comment section.