10 mm auto
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The 10 mm Auto pistol cartridge is the child of the famous firearms expert Jeff Cooper. It was supposed to be a medium velocity pistol cartridge with more stopping power than the 9 mm Luger cartridge and better ballistics then the .45 ACP.
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History
When Norma designed the cartridge with help of Dornaus & Dixon for the Bren Ten pistol, they decided to increase the power of Jeff Cooper's idea. The resulting 10 mm Auto pistol cartridge is very powerful, and combines very good ballistics with excellent stopping power. The 10 mm Auto cartridge is much more accurate than the 9 mm Luger and proportionate to its size more accurate than a .22 LR cartridge.
Originally developed by Dornaus & Dixon and Norma of Sweden in 1983 for the Bren Ten autopistol (a heavily modified CZ-75), the 10 mm Auto has never enjoyed large-scale popularity, but is nonetheless an excellent cartridge. It earned a reputation for battering guns early on, but this was largely due to manufacturers trying to get away with simply rechambering a .45 for the 10 mm Auto. Simply put, a .45 frame and slide cannot handle such a hot round. Later guns were built around the 10 mm and, if properly cared for, worked remarkably for many years and thousands of rounds. The FBI adopted the round in the late 1980s along with the S&W model 1076 (a short barreled version of the 1006). As agents began having difficulty handling full-power 10 mm loads, the FBI submitted a requirement for a "light" loading. This later beacame known as the "10 lite", or "10 mm FBI" load. Smith and Wesson saw an opportunity to create something new: a shortened version of the 10 mm that would function in a 9 mm Luger pistol. The advantage being that smaller-handed shooters could now have a 9 mm sized gun with near-.45 ACP performance. This new round was called the .40 S&W or .40 Smith and Wesson. Unlike the 10 mm Auto, the .40 "short & weak" uses small pistol primers. The introduction of the .40 and its subsequent adoption by nearly every law enforcement agency in the US all but spelled the end for the 10 mm. Today, it is enjoying a bit of a resurgence in popularity, if not a stellar sales jump.
The 10mm Auto is similar in performance to the .41 Magnum, and is a good handgun round for deer.
Performance
This 10 mm Auto cartridge is unique in that it runs nearly twice the working pressure of a standard pistol cartridge, allowing it to develop true "magnum" velocities, while still being fired in a .45 ACP size handgun. Original loading was a 200 grain (13 g) bullet at 1200 ft/s (366 m/s), developing 635 ft·lb (861 J) of kinetic energy at the muzzle. Later loads exceeded 700 ft·lbf (950 J). This is nearly twice the energy of a .45 ACP.
However the 10 mm Auto cartridge turned out to be too powerful to be used by most people, even the FBI which adopted it. Thus the FBI started using lowered charge versions which have a level of performance similar to the .40 S&W cartridge. Another drawback of the 10 mm Auto is the too high "One Shot Kill" level with expanding bullets, a level of performance which far exceeded its design goal of "One Shot Stop".
Muzzle velocity
- 10.9 g (170 gr) full metal jacket: 405 m/s (1330 ft/s)
- 12.9 g (200 gr) full metal jacket: 360 m/s (1180 ft/s)
- 14.3 g (220 gr) LTC, over IMR 800X: 366 m/s (1200 ft/s)
Usage
Currently GLOCK, Kimber, Dan Wesson, STI, EAA, Smith & Wesson and a few others chamber the 10 mm Auto. It is adequate for hunting medium game at moderate ranges, and certainly more than adequate for defensive or tactical use.
Today the 10 mm Auto cartridge is being mainly used to fend off medium sized dangerous animals, or for hunting.
Synonyms
- 10 mm
- 10 mm Norma
- 10 mm FBI