.40 S&W is an American centerfire semi-automatic pistol cartridge introduced by Smith & Wesson and Winchester Ammunition in 1990. It packaged the FBI's reduced-velocity 10mm service-load concept into a shorter cartridge suitable for 9mm-size duty pistols, while SAAMI and C.I.P. standards define the cartridge's pressure and dimensional limits. The strongest documented context is design history, specifications, and firearm compatibility rather than conflict-specific battlefield use.
The FBI 10mm program created the service-load target, Smith & Wesson and Winchester shortened the package for duty-pistol dimensions, and SAAMI/C.I.P. drawings define the pressure and dimensional boundaries.
American Rifleman ties .40 S&W to the FBI's reduced-velocity 10mm Auto concept rather than to full-power 10mm performance.
The shorter case let the cartridge fit smaller service-pistol frames than the original 10mm Auto platform required.
C.I.P. lists 2250 bar Pmax; SAAMI lists 35,000 psi maximum average pressure and names the cartridge 40 Smith & Wesson [40 S&W].
Browning's owner manual gives a direct firearm-specific compatibility statement for .40 S&W Hi Power pistols, while Federal's current handgun-ammunition catalog supports the broader handgun-cartridge context.
| Compatible item | Item type | Compatibility evidence |
|---|---|---|
 | Semi-automatic pistol | Browning's owner manual says .40 S&W Hi Power pistols must be used only with .40 S&W cartridges and lists the .40 S&W Hi Power at 10+1 capacity. |
 | Handgun/pistol platform | Federal lists .40 S&W among its popular handgun calibers. |
An FBI Law Enforcement Bulletin abstract says the FBI Firearms Training Unit began a 1987 effort to identify a new handgun and cartridge, with testing focused on caliber, penetration, and wound size.
American Rifleman describes the FBI-backed reduced 10mm concept as a 180-grain loading around 975 fps, the service-load target that Smith & Wesson later shortened into the .40 S&W package.
Smith & Wesson and Winchester introduced .40 S&W in early 1990 as a shorter 10mm-derived service cartridge for smaller, lighter duty pistols.
SAAMI and C.I.P. standards material both date the .40 S&W cartridge drawing to February 1, 1990, anchoring the cartridge's formal pressure and dimensional references.
