The .45-120 Sharps cartridge, also known as the .45 3¼ inch or .45-120-550, is a large-caliber black powder cartridge originally designed for Sharps rifles in the late 19th century. This cartridge has a bullet diameter of .458 inches (11.63 mm), and typically utilizes a case length of 3.25 inches (82.5 mm). The "120" in its name denotes the original black powder charge of 120 grains.
Use cases for the .45-120 Sharps include long-range shooting and big-game hunting, particularly in the tradition of hunting large North American game like bison. Its long case capacity allows for significant black powder loads, which results in powerful ballistic performance, but also considerable recoil.
This cartridge saw its heyday in the late 19th and early 20th centuries and is now generally considered a specialty round among black powder cartridge enthusiasts and historical firearm collectors. Modern uses are more niche, often focused on the aspects of traditional marksmanship and historical reenactment.