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.
Artillery
After the British artillery was shown up in the Crimean War as having barely changed since the Napoleonic Wars the industrialist William Armstrong was awarded a contract by the government to design a new piece of artillery. Production started in 1855 at the Elswick Ordnance Company and the Royal Arsenal at Woolwich, and the outcome was the revolutionary Armstrong Gun, which marked the birth of modern artillery. Three of its features particularly stand out.
First, the piece was rifled, which allowed for a much more accurate and powerful action. Although rifling had been tried on small arms since the 15th century, the necessary machinery to accurately rifle artillery was not available until the mid-19th century. Martin von Wahrendorff, and Joseph Whitworth independently produced rifled cannon in the 1840s, but it was Armstrong's gun that was first to see widespread use during the Crimean War. The cast iron shell of the Armstrong gun was similar in shape to a Minié ball and had a thin lead coating which made it fractionally larger than the gun's bore and which engaged with the gun's rifling grooves to impart spin to the shell. This spin, together with the elimination of windage as a result of the tight fit, enabled the gun to achieve greater range and accuracy than existing smooth-bore muzzle-loaders with a smaller powder charge.
His gun was also a breech-loader. Although attempts at breech-loading mechanisms had been made since medieval times, the essential engineering problem was that the mechanism couldn't withstand the explosive charge. It was only with the advances in metallurgy and precision engineering capabilities during the Industrial Revolution that Armstrong was able to construct a viable solution. The gun combined all the properties that make up an effective artillery piece. The gun was mounted on a carriage in such a way as to return the gun to firing position after the recoil.