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.
Rifled musket
Rifles were more expensive to make than muskets, and were typically used by small units of specialized riflemen trained not to fight in closed ranks, but in open order, spread out as skirmishers or sharpshooters. Since they were not fired over other men’s shoulders or designed for close-combat bayonet fighting, military rifles could be much shorter than muskets, which also made loading from the muzzle easier and reduced the difficulties associated with fitting the bullet into the barrel, although the rate of fire was still slower than that of a musket. 
The problem of slow loading of rifles caused by barrel fouling was solved by the Minié ball, which was invented in the 1840s by French inventor Claude-Étienne Minié. Despite its name, the Minié ball was not a round ball at all - it was long and conical, with an expanding skirt at the rear of the bullet. The skirt allowed the minié ball to be smaller than the barrel's bore, so it would slip in as easily as the ball of a smoothbore. When the weapon was fired, the skirt expanded to fit tightly against the inside of the rifle barrel, with less energy wasted in blow-by around the projectile and insuring that the rifling lands and grooves would impart a stabilizing spin to the minié ball.