10mm Auto
The backcountry carry favorite — real power in a duty-size auto, though many commercial loads are watered down to near-.40 levels, so label-reading matters.
Family
Handgun
Introduced
1983
Origin
Jeff Cooper concept, Norma, Sweden/USA
History
Championed by Jeff Cooper and loaded by Norma for the ill-fated Bren Ten pistol in 1983, the 10mm Auto was pitched as the ultimate service auto cartridge. The FBI adopted it after the 1986 Miami shootout but found full-power loads hard to manage, spawning the .40 S&W. It has since found a devoted second life among outdoorsmen wanting serious power in a semi-auto.
What it's used for
Iconic platforms
Glock 20 and 29, Colt Delta Elite, Smith & Wesson M&P 10mm, SIG P320 XTEN, and 10mm 1911s.
Common load types
FMJ, jacketed hollow point, and hard-cast or bonded 'woods' loads for animal defense.
Reference only — not loading data, not ballistics advice, and KitID links to no ammunition sellers. Know your local law before you buy anything that goes bang.