When Smith & Wesson ushered in the metallic cartridge era in American handgunning, .31 caliber was already established as the de facto standard for repeating pocket pistols, with many thousands of Colt's Pocket Models and various small pepperboxes already on the market. It was only natural then, for Smith's second cartridge to be a rimfire .32; roughly the same size as the existing muzzle loading offerings.
RIGHT: S&W Model One-and-a-Half top break, in .32 S&W.
In the 1870s, the .32 made the jump to the centerfire era in Smith's tiny "Model One-and-a-Half", and when they went to solid-frame revolvers with swing-out cylinders, S&W retained the caliber, albeit with a lengthened case, as the ".32 Smith & Wesson Long".
LEFT: .32 Hand Ejector 3rd Model in .32 S&W Long.
When John Browning turned his attentions to self-loading pistols, his first commercial success in the arena was the Model 1900 produced by Fabrique Nationale in Belgium. It was a slim little automatic pistol that could fit easily into a coat pocket and although nearly everything else about it was new, the bore diameter was the old familiar .32; the bore size that had become popular with a muzzle-loaded lead ball seated over patch and powder now saw a pistol that used smokeless propellant to launch a jacketed bullet and then reloaded itself. Known as 7.65 Browning in Europe, the cartridge was sold as the .32 ACP (for Automatic Colt Pistol) in the USA, since its first appearance on these shores was in the Colt's 1903 Pocket Hammerless.
RIGHT: Colt's Model 1903 Pocket Hammerless in .32ACP.
.32, in both revolver and automatic formats, was very nearly the default bore size for pocket defensive guns for over a century and, as earlier competitors fell by the wayside, .32 S&W Long and .32 ACP became the default cartridges for .32-caliber pocket arms worldwide. Given that both revolvers and pistols of this type have been produced in nearly every country sophisticated enough to have an arms industry and even a few that aren't, there is no telling how many countless millions of these diminutive weapons lie forgotten in the sock drawers, sea chests, and sideboards of the world despite all the fantasy schemes of governments to control them; one may as well command the tide.
LEFT: Filipino blacksmith-made copy of S&W I-frame (top) and original S&W I-frame (bottom).
In addition to Smith & Wesson and Colt's (who called it the ".32 Colt New Police,) which were seen as the high end of the market, numerous other American companies manufactured .32 S&W Long revolvers: Iver Johnson, Harrington & Richardson, and Hopkins & Allen, to name but a few. Sold in hardware stores and via mail order, they were as common as Kleenex in purses and glove boxes.
During the early 20th Century, in addition to the well-known Pocket Hammerless model from Colt's, hundreds of thousands of which were manufactured over some forty years, pocket automatics in .32ACP were sold by Savage, Remington, and H&R; untold more were imported from Europe via regular importation channels as well as in the duffle bags of generations of American servicemen.
In postwar America, with the development of small .38 revolvers, often on .32-sized frames, and a general reduction in the pocket pistol market following the hostile legislation enacted in 1968, .32 in both "ACP" and "S&W Long" forms gradually became the caliber of the much-demonized "Saturday Night Special", found largely in extremely inexpensive revolvers and cheap cast zinc pistols. The fact that these guns served a valuable purpose in a market where a traditionally-made blued steel firearm, produced by union labor in New England and excise taxed to death, could cost half a month's wages for a night clerk went unmentioned.
RIGHT: The Beretta 3032 Tomcat, which hit the market in 1996, was one of a wave of new pocket pistols in .32ACP.
While .32 S&W Long lingers on mostly as a chambering for esoteric ISSF target pistols and a reduced load for various .32-caliber magnums, .32ACP has seen something of a revival in the last decades, with the reform of concealed carry laws and the introduction of truly tiny pocket guns from innovators such as Larry Seecamp and George Kellgren as well as established makers like Beretta. Whether the .32 will see its second century or not remains to be seen, but given its ubiquity, that would seem to be the way to bet.