Sometimes, a good loading just can’t get a break. The 10mm was introduced in 1983, based on suggestions from Jeff Cooper. He’d imagined a cartridge that could match the speed and flat trajectory of the 9×19mm with the heavier projectile of a .45 ACP, basically splitting the small/fast vs. large/slow debate down the middle.
This had been tried before, of course. The .41 Magnum was an earlier attempt to reconcile the .357 and .44 Magnum loadings. Based on the .400 Eimer wildcat cartridge, it could propel a 210gr bullet at 1520 ft/s, dumping a biblical 1080 ft/lbs of energy (1). Sadly, the .41 never caught on, and it faded into a sort of semi-obscurity, kept afloat by reloaders and aficionados who saw its potential in a wide range of loadings.
I wonder if it might have succeeded given a catchier name…something like .400 Lightning. Or the Four Bore Groin Punch. Who knows?
The 10mm started as a similar bit of an odd bird. Cooper had in mind a .400 caliber, 200gr bullet travelling at ~1000 ft/s. Pretty neat. What Dornaus & Dixon produced for use in their Bren Ten pistol was even more impressive, however. Produced with input from Roy Weatherby, Norma’s original loadings sent a 200gr bullet downrange at ~1200 ft/s, dumping over 600 ft/lbs of energy.
Ladies and gentlemen, we had ourselves a true Magnum-class autoloader.
Unfortunately, the Bren Ten was plagued by manufacturing and supply problems, and they gave up the ghost in 1986. The following year, Colt released the Delta Elite, which was a 1911 chambered for the cartridge.
The Delta Elite is a marvelous pistol, and one I’ve never shot before. The above group was shot cold with a customer’s pistol at 30′. I’m guessing it would have shot better than I could, given a bit more time.
The 10mm was a bit of a “specialty” cartridge until 1986, when the FBI decided that the 9mm was completely inadequate as a combat round. I’ll leave it up to the historians to debate the matter, but I disagree with that on several levels. But that’s another story.
The Bureau needed something that could punch through car doors, as well as the bones and organs of really angry and motivated Army Rangers who’d taken to robbing armored cars and killing folks. Thus, the 10mm entered a wider stage.
S&W answered the call with their 10-series. The 1006 and 1076 were initially adopted by the FBI, but it turned out that the original loadings were a bit much for most agents, even out of a heavy steel frame. Powder was yanked, and the loadings were gradually watered down. Eventually, the mighty load I mentioned above became a 180gr bullet sauntering along at 950 ft/s.
If those ballistics sound familiar, it’s because they’re identical to what we know today as the .40 S&W (2). See, somewhere along the line, somebody realized that so much propellant had been removed, you could just shorten the case while you were at it. The newer cartridge could easily fit in smaller pistols, and it took off like wildfire. Today, the .40 is the dominant cartridge with most law enforcement agencies East of the Mississippi.
Still, there’s something to be said for the 10mm. There are hunters out there who swear by it, and it’s quite popular among handloaders (who are basically the white-hat hackers of the shooting world). I don’t know if we’ve become more tolerant of recoil over the decades, but I really don’t mind shooting the 10. Out of a reasonably weighty gun, it’s quite entertaining without turning brutal.
I can’t say the same for polymer-framed pistols in .40 S&W, which I find quite unpleasant, particularly in smaller sizes.
At the moment, there are few pistols chambered for the round. EAA and Tanfoglio make clones of the CZ-75 chambered for it, and Glock makes the 20 and 29. Colt is bringing the Delta Elite back into production later this year, and Vltor has a very interesting reinterpretation of the Bren Ten in the works. Kimber and several other companies make mid-to-high end 1911s in 10mm as well.
Smith & Wesson also makes the 610, an N-Frame revolver. So, basically, it’s a roundabout Model 57. What a long trip…
None of this is likely to spark a revival of the 10mm on a wide scale, but it’s enough to keep a good loading alive.
(1) Modern loadings are 210-220gr bullets at 1280 ft/s, with 629 ft/lbs of energy.
(2) Don’t yell, I’m getting to it! Older folks will recognize those same numbers as pertaining to the venerable .38-40 Winchester.