The .50-110 Winchester (also known as the .50-100-450 Winchester, with different loadings) is an obsolete American black powder centerfire rifle cartridge.
Introduced in 1899 for the Winchester Model 1886 repeater, the .50-110 Winchester was also available in single-shot weapons such as the Winchester 1885 Hi-Wall. Slight variations in charge weight in the same case led to the mistaken belief these were different rounds, when in fact they were not.
Designed for black powder, the .50-110 was also available in a potent smokeless loading, comparable to British elephant rounds. In power, the standard load was comparable to the contemporary British .500 Black Powder Express, It is sufficient for elk, deer, moose, or bear at medium range or in woods, and thin-skinned African game, but not dangerous animals such as elephant. The high-velocity smokeless load was in a class with the .444 Marlin, and its power exceeded the .348 and .358 Winchester.
Winchester continued to offer the cartridge commercially until 1935 and while it is still offered by some suppliers, due to its obsolescence and resultant obscurity, it is significantly more costly than more current cartridges — averaging from US$3 to $4 per round.