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.
Mitrailleuse
The 13 mm centerfire Reffye mitrailleuse cartridges were loaded into interchangeable steel breech blocks, unlike the Montigny mitrailleuse, whose ammunition was held by the cartridge base in plates. When firing the mitrailleuse, three breech blocks were kept in continuous use: one being fired, one being pressed down on the extractor and one being loaded from a single pre-packaged 25-round box. Adjusting the elevation of the mitrailleuse in accordance to the distance to the designated target was performed with an elevating screw identical to that on a regular artillery piece. The mitrailleuse's barrel could also be moved sideways while firing, to the right and left, in order to adjust for range and provide lateral sweeping fire if needed. The lateral sweep was narrow, however, thus most effective at far distances only. The weapon's field of fire was so narrow that Prussian soldiers were often hit by several bullets at once. During an early engagement of the Franco-Prussian War, at Forbach in Alsace on August 6, 1870, a Prussian general officer (General Bruno von François) was brought down by a very closely spaced volley of four bullets. According to the Prussian regimental record, those four mitrailleuse bullets had been fired from 600 meters away. French artillery attempted to rectify this problem by developing special ammunition capable of firing three bullets from the same cartridge for short-range point-defence.