The .577 Black Powder Express is a large caliber hunting cartridge originating in the United Kingdom and a series of case lengths.
It is a centerfire, black powder hunting rifle cartridge that comes in three different casing lengths; 2¾", 3", and 3¼".
These cartridges were designed for shooting softer-skinned game animals, including dangerous beasts such as lions, tigers, and wild boars.
The 3" case length lived on into modern times as the .577 Nitro for Black, which used mild loadings of cordite smokeless propellant carefully balanced to replicate the ballistics performance of the original black powder loads.
In addition, all three casing lengths were also used to create the .577 Nitro Express cartridge, with the 3" version becoming the most popular.
According to African Rifles and Cartridges by John "Pondoro" Taylor, it was the most popular cartridge in India for hunting tigers, and that many of the greatest lion hunters in Africa used the .577 Black Powder Express in preference over anything else.