The Perfect 10

I have been reading gun magazines and shooting since I was a teenager. I am in the industry, and I live and breathe this stuff. Still, things can still happen that leave me completely bewildered, including unexpected events that no one, seemingly, sees coming — and I’m not even referring to political-­driven sales and slumps! About a decade ago, the 10mm Auto cartridge began its resurgence, and I have still yet to fully understand it.

I haven’t quite figured out why the 10mm is more popular than ever. I think it first got noticed as a good choice for bear defense, fueled by ammunition developments such as the Federal 180-grain Trophy Bonded Bear Claw. Some 10 years ago, backcountry hunters became open-minded to higher capacity 10mm handguns versus waning interest in packing a hard-recoiling wheelgun in .44 Magnum, .454 Casull, .480 Ruger or .500 S&W Magnum. I don’t know how many people actually venture into areas where there are bears, but how many of us fastrope out of helicopters and do CQB? Still, there are many who want the latest pistol employed by U.S. Special Forces.

If you were into guns during the 1980s, the 10mm needs no introduction. For everyone else, allow me to start at the beginning: Just as John Browning designed the .45 ACP in 1904 for his full-size pistols, the 10mm Auto was developed from the early ’70s .40 G&A wildcat for the Bren Ten. Both the 10mm cartridge and the Bren Ten were introduced in 1983, but the Bren Ten was plagued with problems.

Dornaus & Dixon designed the pistol around the cartridge with input from Norma and Lt. Col. Jeff Cooper, one of the most influential people in the handgun world and a former Guns & Ammo handgun editor. The Bren Ten was a double-action (DA)/single-action (SA) pistol influenced by the CZ 75, which was a pistol Cooper approved of. The full-­size Bren Ten models sported 10-­round magazines, two or three rounds more than the .45 M1911. As iconic pistols go, the Bren Ten is at the top of the list. Don Johnson even carried one as “James ‘Sonny’ Crockett” during the first two seasons of “Miami Vice.” That gun featured a hardchromed slide to look better on camera, and every male over the age of 14 in America wanted one as much as they did his black faux-­Ferrari Daytona.

The manufacturer had serious problems delivering the pistols; magazines were even scarcer. By 1986, Dornaus & Dixon were bankrupt. In Season 3 of the show, “Crockett” switched to a Smith & Wesson Model 645 before settling on the 4506 in subsequent seasons. The Bren Ten died with a whimper, and the 10mm cartridge might have followed it but, in 1987, Colt introduced the Delta Elite in 10mm while S&W came out with the Model 610 revolver. S&W also launched a ­series of semiautos (i.e., 1006, 1076, etc.) starting in 1990, and Glock revealed the G20 in 1991. For 20 years, the 10mm limped along, at times ­forgotten, until its recent resurgence.

Pistols in 10mm were never going to be popular, in part due to the cartridge. It was designed to be the “ultimate” self-­defense cartridge for semiauto pistols, providing the best balance of power and magazine capacity. It was, perhaps, too much of a good thing — and darn near a .41 Magnum in power and recoil! Original Norma loads featured a 200-­grain bullet at 1,200 feet per second, as well as a 180-­grainer at 1,300 fps. Those were more stout than most modern 10mm loads.

The 10mm Auto is roughly the same length as the .45 ACP, 1.26 inches versus the .45 ACP’s 1.275 max overall length (OAL). This means the 10mm only fits large pistols. The parent case of the 10mm was the .30 Remington. It used a large pistol primer, and was stuffed with a .40-inch bullet. In the early ’80s, hollowpoints were few and not guaranteed to expand. Hence, most folks preferred bigger bullets. Elmer Keith said, “A big bullet lets in a lot of air, and lets out a lot of blood.” The .40-caliber 10mm was considered the bare minimum bullet diameter for a “fighting” pistol cartridge. However, it provided more magazine capacity than the gold standard of semiauto cartridges, the venerable .45 ACP.

The 10mm enjoys a near-­mythical status. Most ’80s handgunners sought a Delta Elite. However, Norma’s initial 10mm offerings were somewhere between brutal and stout in a M1911. The early Delta Elites suffered a reputation for frame cracks and breakages. That didn’t stop people from buying them, though. Though the FBI initially bought S&W’s Model 1076, the order was canceled. The first 10mm pistol that had a reputation for being capable of handling the recoil of the 10mm was the Glock 20.

I wasn’t immune to the lure of the 10mm. I owned an Olympic Arms AR-­15 top-­end chambered in 10mm, a straight blowback design fed by modified “Grease Gun” magazines. I handloaded stupidly hot ammo for it: 180-­grainers at 1,600 fps. Later, in the early 2000s, my USPSA Limited Division pistol was a hard-chromed custom wide-­body 1911 chambered in 10mm. (I carried it daily.)

In part, the 10mm faded away due to the development of the .40 S&W by Smith & Wesson and Winchester in 1990 — and the FBI. The 10mm passed the FBI’s Ammunition Testing Protocol, but it was said to be too much to handle for some agents, both physically and in terms of felt recoil. The FBI explored a downloaded version of the 10mm, the “10mm Lite,” but the cartridge was still the length of a .45 ACP. The ballistics of the 10mm Lite were then duplicated in a shorter cartridge, which became the .40 S&W. The .40 S&W was hugely popular, almost killing the 10mm for nearly 20 years. Of course, there were outliers. Ted Nugent was famous for carrying a Glock 20 loaded with CorBon 135-­grainers at 1,500 fps, and hunting big game around the world with it. Heckler & Koch even built some MP5s chambered in 10mm for the FBI — the MP10 — which were highly coveted and rare.

For whatever reason, a new generation of shooters discovered the 10mm. The Glock 20 was still around, and Colt relaunched the Delta Elite in 2013. Other manufacturers took note of the public’s interest in the 10mm and started producing new designs.

SIG Sauer announced the 10mm P220 in 2014. Springfield Armory released its XDM 10mm in 2019. Today, almost every 1911 manufacturer offers a model chambered in 10mm. SIG Sauer even announced the P320 in this caliber in 2022, the P320-XTen. CMMG, and a few other companies, make Black Rifles chambered in 10mm, and this cartridge really shines out of longer barrels. EAA, Ed Brown, FN, Hi-­Point, Rock Island Armory, Ruger, Smith & Wesson, all have models chambered in 10mm — and the list goes on. While I was writing this article, Taurus introduced its TH10, a DA/SA polymer-­framed 10mm. 

It’s not just guns — just about every ammunition manufacturer offers several 10mm loads. Hornady even offers a non-leaded MonoFlex Handgun Hunter load. While not nearly as popular as other calibers, the 10mm is no longer a niche, hard-­to-­find caliber. 

More options are always better, and the 10mm performs — especially with modern bullets. Now if we could just get somebody to bring back the Bren Ten, all would be right with the gun world.

Sound Off

What are your thoughts on the 10mm? Have any favorite 10mm handguns that we missed? Do you think it's comeback has any staying power? Let us know by emailing gaeditor@outdoorsg.com using "Sound Off" in the subject line.

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