The 40-90 Sharps cartridge is a large, black powder cartridge originally developed in the late 19th century for use in Sharps rifles. These rifles were popular for hunting and long-range target shooting and were especially known for their use on the American frontier. The designation ".40-90" refers to the .40 inch (10.16 mm) caliber bullet and the 90 grains (5.83 grams) of black powder used as the propellant.
The cartridge is notable for its straight-walled design, which made it less susceptible to fouling than bottleneck cartridges and easier to reload. It was primarily used for hunting large game such as bison and elk due to its powerful performance. The 40-90 Sharps had a reputation for accuracy and stopping power at long ranges. However, its use declined with the advent of smokeless powder and more modern cartridges. Today, it holds historical significance and is of interest to collectors and black powder shooting enthusiasts.