Mitrailleuse
A mitrailleuse (; from French "mitraille", "grapeshot") is a type of volley gun with multiple barrels of rifle calibre that can fire either multiple rounds at once or several rounds in rapid succession. The earliest true mitrailleuse was invented in 1851 by Belgian Army captain Fafschamps, 10 years before the advent of the Gatling gun. It was followed by the Belgian Montigny mitrailleuse in 1863. Then the French 25 barrel ""Canon à Balles"", better known as the Reffye "mitrailleuse", was adopted in great secrecy in 1866. It became the first rapid-firing weapon deployed as standard equipment by any army in a major conflict when it was used during the Franco-Prussian War of 1870–71. A steel block containing twenty-five 13 mm (.51 calibre) centre-fire cartridges was locked against the breech before firing. With the rotation of a crank, the 25 rounds were discharged in rapid succession. The sustainable firing rate of the Reffye mitrailleuse was 100 rounds per minute. The maximum effective range of the Reffye "mitrailleuse" was about 2000 yards; a distance which placed their batteries beyond the reach of Prussian Dreyse needle rifle fire. Reffye mitrailleuses were deployed in six gun batteries and were manned by artillery personnel. They were not infantry support weapons, but rather a form of special artillery.
John Pedersen (arms designer)
Many of Pedersen's U.S. military efforts were stymied by fate. Although the Navy recommended adoption of his .45 pistol design, the outbreak of World War I led to the design being shelved in favor of the M1911 pistol already in production for the Army. His most famous invention, the Pedersen Device, never had a chance to significantly affect the battles on the Western Front during World War I: the war ended before it could be manufactured in quantity and sent to France to equip the American Army (only 65,000 were produced out of planned production of 500,000). In the 1920s U.S. Army Ordnance selected his .276 Pedersen cartridge to replace the .30-06 in the infantry rifle and tested Pedersen's unique toggle-linked semi-automatic rifle in competitions at Aberdeen Proving Ground. The Pedersen rifle lost out to the rifle designed by John C. Garand. General MacArthur later vetoed the adoption of .276 Pedersen as the new infantry cartridge. General George S. Patton owned a Remington Model 51 and was thought to favor the weapon and is seen in many photos of the era wearing it as his personal sidearm. During World War II, John Pedersen's attempts through the Irwin-Pedersen Arms Company to mass-produce M1 Carbines for the U.S. military failed.