.40 S&W
.40 S&W's snappier recoil and the FBI's return to 9mm ended its duty-era dominance, but police trade-in pistols make it one of the best used-gun bargains going.
Family
Handgun
Introduced
1990
Origin
Smith & Wesson and Winchester, USA
History
Born from the FBI's reduced-power 10mm load after the 1986 Miami shootout, the .40 S&W of 1990 packed that ballistic recipe into a 9mm-sized frame. It dominated American law enforcement for two decades, with most major agencies issuing it. The FBI's return to 9mm in the mid-2010s started an industry-wide migration back, and .40 has been receding since.
What it's used for
Iconic platforms
Glock 22/23, Smith & Wesson M&P40, SIG P226/P229 — the classic duty pistols of the 1990s and 2000s.
Common load types
FMJ practice loads and 165- or 180-grain jacketed hollow points.
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.