Even though the 10 mm cartridge is about 40 years old, admittedly I’ve not paid much attention to it. And while its popularity has ebbed and surged a couple of times since its introduction, it seems that it’s now here to stay—based on the number of manufacturers that continue to produce pistols in this powerful chambering. A little late to the show, I decided to finally check into it.
History
The concept of a 10 mm cartridge was conceived of and developed in the early 1980s by Colonel Jeff Cooper, father of the “Modern Technique of the Pistol” and founder of the renowned Gunsite Academy. He desired the supreme combat pistol, specifically one that could eject a 200-gr. bullet at 1200 fee per second (f.p.s.). Cooper worked in conjunction with a company named Dornaus & Dixon which, in 1983, manufactured the first stainless steel, semi-automatic 10 mm handgun—the Bren Ten (IMFDB image). The pistol was made and sold from 1983 to 1986, with a limited production of about 1,500 pistols, but was discontinued after the company was forced into bankruptcy due to a series of issues with the gun’s magazines. 
If you ever see one for sale, get ready to shell out about $8,000, as they are a highly sought-after collector’s item, having gained an enormous following by fans of the classic 1980s TV show “Miami Vice.” The show’s main character, Sonny Crockett, played by Don Johnson, carried a Bren Ten for the first two seasons before switching to a Smith & Wesson Model 645, in part because there were not enough 10 mm blanks being produced.
Interest in the 10 mm has periodically risen and fallen since its introduction. It was even adopted as the official chambering for Smith & Wesson semi-automatic handguns used by the FBI for a few years starting in 1989, as a response to the notorious 1986 "Miami Shootout" in which agents found themselves outgunned by two men. But the cartridge was later decommissioned and replaced by the .40 S&W, which was introduced in 1990. Following the Bren Ten, the Colt Delta Elite was the first firearm produced by a major manufacturer to chamber the 10 mm, but it, too, was dropped from production in 1996 due to sluggish sales and competition with the .40 S&W. The Delta Elite, however, was reintroduced in 2009.
The current uptick in interest in the chambering is largely due to the cartridge’s ballistics. “The resurrection of the 10 mm is attributed to the sweet spot the 10 mm hits between the 9 mm and the .45 ACP in regards to upping the bullet weight from the 9 mm closer to .45 ACP territory,” says Winslow Potter, director of product marketing, Kimber Mfg. “The 10 mm also ups the velocity of those heavier bullets closer to and exceeding the velocities found in many of the 9 mm cartridge offerings, including +P.” (Shown: Kimber Camp Guard in 10 mm)
Self–defense: The 10 mm beats the 9 mm for self-defense for frontal surface area and penetration because of the higher velocity. With a 10 mm pistol, a 180-gr. bullet moves at about 1300 f.p.s. With a 9 mm, 147-gr. bullet, the speed is about 950 f.p.s. “So with a 10 mm you’ve got several hundred feet per second more, and the projectile is larger, so it’s going to create a bigger wound cavity,” says Sergeant Major Kyle Lamb (US Army, retired), and president of Viking Tactics. “If you have a bullet that’s bigger and it’s going faster it’s going to cause more damage.” The 10 mm could travel more than 17 inches after impact, compared to the 9 mm, is capable of traveling 13 inches after impact.
Hunting: The 10 mm is ideal for hunting, especially on medium game like deer or hogs, or if you find yourself in a defense situation against bears. “For hunting, I think the 10 mm is a great cartridge,” says Lamb. “For hunting medium game, I would recommend the 10 mm. I have a 10 mm, and I plan on taking it hunting.”
Just keep in mind the recoil increases significantly when compared to a 9 mm, so practice as often as possible.
Self-defense: They also have more recoil, and a reduction in magazine capacity. “To me, the reduction in capacity is a big negative,” says Lamb. “For example, with a 9 mm Glock 17, you get 17 rounds. But with the Glock 20 (shown), 10 mm, you get 15 rounds.” In a self-defense situation, you want as many rounds as possible in your magazine so you don’t have to waste precious seconds changing mags.
At the range: Regarding target practice, this is one area where the 9 mm outshines the 10 mm. Because 9 mm is less expensive to shoot, recoils less, and more readily available, the 10 mm loses when it comes to range time.
The 10 mm is fine for most competition, however, the brass is far more expensive than a .40. Also, the power factor is such that some shooters end up moving down from the 10 mm to that of a .40 for less recoil and faster on-target acquisition.
Regarding grip, since 10 mm pistols are typically larger than those chambered for 9 mm, getting a good, firm grip is going to be an issue if you have small to medium hands. Most 10 mm guns are larger and heavier by nature because a longer barrel is necessary to make the most of the 10 mm cartridge’s heavier bullet and larger case capacity.
If you are considering moving up to a 10 mm handgun, there are now countless models available—including the many revolvers that now chamber the round (Shown: Ruger GP 100 Match Champion). Find an indoor range that will let you rent one, and fire away. All the experts I interviewed for this piece recommended not to purchase one without shooting it first, because you are going to notice the heavier recoil, the larger size, and the diminished capacity. As far as accuracy goes, more recoil could affect your accuracy. 
“The 10 mm is an awesome cartridge,” says Lamb. “If you can handle the recoil, and you don’t mind the size of that pistol then by all means go for it, especially of you are going to go hunting.”
