The .44-40 Winchester is a historic American cartridge introduced in 1873, originally chambered in both rifles and revolvers of the frontier era. A cornerstone of Old West firearms, it remains popular today for cowboy-action shooting and historical recreation.

The .44-40 Winchester was introduced in 1873 for the Winchester Model 1873 lever-action rifle, and its name follows the old convention of .44 caliber with an original 40-grain black-powder charge. It became one of the defining cartridges of the American West, notable for being widely chambered in both lever-action rifles and revolvers — a shooter could carry one cartridge for both, a meaningful convenience on the frontier. Ballistically the .44-40 fires a .42/.44-caliber bullet at modest velocity, with performance reflecting its black-powder-era origins, though it has long been loaded with smokeless powder for modern firearms. It is effective for hunting at close range and for the recreational and historical roles where it sees most use today, with mild recoil in the firearms built for it. Its enduring identity is historical. It is a mainstay of cowboy-action shooting — the sport built around Old West firearms — and is favored by enthusiasts of historical and replica guns. That cultural significance, more than any modern ballistic advantage, is what keeps it in production a century and a half after its introduction. Today the .44-40 Winchester is used for cowboy-action shooting, recreational and historical shooting, and close-range hunting, with steady ammunition availability supporting those roles. Its combination of deep frontier heritage and rifle-and-revolver versatility is why this 1873 cartridge remains in active use.

General information about this caliber — not a recommendation for this specific firearm.