Hiram Berdan was an American engineer, inventor, military officer, marksman, and guiding force behind and commanding colonel of the United States Volunteer Sharpshooter Regiments during the American Civil War. He was the inventor of the Berdan rifle, the Berdan centerfire primer and other weapons and accessories.

The Berdan rifle is a single-shot rifle created by American engineer and inventor Hiram Berdan in 1868. It was the service rifle of the Imperial Russian Army from 1870 to 1891, when replaced by the Mosin–Nagant rifle. The gun was widely used in Russia as a hunting weapon, and sporting variants, including shotguns, were produced until the mid-1930s. The Russian Berdan I (M1868) and Berdan II (M1870) rifles of .42 caliber are distinct from the Spanish Berdan 15 mm (0.591 in) conversion rifles adopted by Spain as the M1857/67 Berdan.