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The 10mm Automatic

By Chuck Hawks

10mm Auto
Illustration courtesy of Hornady Mfg. Co.

Norma brought the 10mm Automatic cartridge to life in 1983, for the Bren 10 pistol. The demand for this cartridge and a gun to shoot it was created by the efforts of various vocal gun writers and proponents of big bore pistol cartridges, in much the same fashion as they had whipped up demand for the earlier .41 Magnum revolver cartridge.

The 10mm Auto approaches the .41 Magnum in power. It is capable of driving a 175 grain bullet at muzzle velocity (MV) of 1290 fps from a 5.5" barrel. This load is available from Winchester with a Silvertip JHP bullet. Needless to say, it is plenty powerful, with 649 ft. lbs. of muzzle energy (MV). As you might suspect, this load kicks like a .41 Magnum, too.

Reloading for the 10mm Auto is straight forward, and the 10mm uses the same .400" bullets as the .40 S&W. The popularity of the latter cartridge insures a decent selection of bullets. The fifth edition of the Nosler Reloading Guide shows that 9.5 grains of HS6 powder behind their 150 grain JHP bullet gives a MV of 1156 fps, and 10.5 grains of HS6 gives the same bullet a MV of 1290 fps. These loads used Winchester cases and WLP primers, and were tested in a 6" pistol barrel.

Note: A complete article about the 10mm Auto can be found on the Handgun Cartridges page.

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Copyright 2004, 2012 by Chuck Hawks. All rights reserved.