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 battlefield use of the mitrailleuse as artillery was a fatally flawed concept. To avoid being hit by Dreyse rifle fire, the mitrailleuse batteries were systematically deployed beyond about 1,400 m (1,500 yards) from the Prussian lines. Although the maximum range of the mitrailleuses was 3,400 m (3,700 yards), the distances at which they were typically engaged rarely exceeded 2,000 m (2100 yards) which was less than the reach of French field artillery. However accurate fire at 1500 yards was always extremely difficult to achieve with the typical open sights present on the mitrailleuse. For instance, mitrailleuse bullet impacts on the ground could not be observed in the far distance unless enemy ranks had been disrupted by hits from them. It may be noted that modern machine guns are typically used at ranges far shorter than their maximum range—the M60 machine gun, for instance, is normally used at an effective range of 1,100 m (1,200 yards), compared to its maximum range of 3,725 m (4,074 yards). The mitrailleuse, by contrast, was often used at the outer edges of its range and without the benefit of optical range finding equipment. These deficiencies in the operational usage of the Reffye mitrailleuse proved disastrous in the Franco-Prussian War.