The .44-40 Winchester cartridge, also known as the .44 Winchester, the .44 WCF (Winchester Center Fire), and the .44 Largo (in Spain), is a centerfire rifle and handgun cartridge that was introduced by Winchester in 1873 as a replacement for the .44 Henry cartridge.

The .44-40 cartridge was designed specifically for the Winchester Model 1873 lever-action rifle and quickly became a popular cartridge for western cowboy guns. The cartridge held 40 grains of black powder and a 200- to 250-grain bullet, and it was capable of producing velocities of up to 1,245 feet per second.

The cartridge was used extensively in the late 19th and early 20th centuries for hunting, target shooting, and self-defense. It was also the cartridge of choice for many law enforcement agencies, including the Texas Rangers.

As technology advanced, Winchester and other firearm manufacturers produced firearms that were chambered for more modern cartridges. However, the popularity of the .44-40 cartridge continued to endure, with many cowboy action shooters and reenactors still using firearms chambered for this historic cartridge today.