During the Franco-Prussian War (1870-1871), Mr. Benjamin B Hotchkiss, an American inventor, was engaged in supervising the manufacture of metallic cartridges for small-arms for France and, his attention being attracted to the defects of the Mitrailleuse, he set about the design of a Machine Gun that should be more practical.
The limitations of the Mitrailleuse, especially when used against skirmishers or troops in dispersed order led him to the adoption of shells as the standard projectiles of his gun. The had forbidden all European Powers from the use of exploding ammunition in warfare where the weight of the projectile was less than 400 grammes (14 oz.) and this dictated the minimum calibre of Hotchkiss' machine gun. He adopted for his first guns a calibre of 37 millimetres (1.45 inches) and a weight of projectile of 455 grammes (1 lb.).
Hotchkiss Design from 1874
Hotchkiss Design from 1879
French Sailors Manning 37mm Hotchkiss
Hotchkiss 6 pdr Quick Firer (Explosion museum)
The Hotchkiss Revolving Cannon consists of a group of five barrels clustered about a common axis which are revolved in front of a solid, immovable breech-block. Cartridges are fed into the breech via a hopper. Turning a hand crank causes the automatic loading, firing and extraction of the empty cartridge-cases, all actions being performed continuously during movement of the crank. The barrels do not rotate continuously about the axis. Instead they are held stationary whilst loading, extracting and firing, then the barrel assembly is turned through a fifth of a revolution, which positions a freshly loaded barrel in front of the firing pin.
Provided that the ammunition supply can be maintained, the revolving cannon can deliver 60 - 80 explosive shells per minute to a range of about 4,000 m. In sea service, when firing from a moving ship against a high speed target, about 15 aimed shots can be fired a minute.
Due to the construction of the gun, and through careful choice of the shell size and propellant charge, there was no recoil, and so it was possible for the gun to be aimed and fired by one man from a suitable mounting. The land service gun, once laid on its target, did not recoil and did not have to be repositioned between each shot.
The first prototypes were made in 1871, but were too late to be used in the war. Hotchkiss spent the next two years developing the gun, and by 1873 it was ready for trials by the French Ministry of Marine. In July 1873, extensive trials were carried out at Gavré which resulted in a further two years of development and experiment. In 1875 the Hotchkiss Revolving Cannon was adopted for service in the Brazilian army, and used to arm torpedo-boats of the Argentine navy. It was also purchased by the Chinese, United States and other Governments.
By 1876, the high-speed torpedo-boat had emerged as a major threat to capital ships, and the French Navy required a gun specially adapted to repel torpedo-boats, to repulse boarders and for boat-service. The Naval model Revolving cannon was adopted for the armament of ships and boat in 1877, and in 1878 the French Navy ordered several hundred to arm their ships. By 1880, 37 mm naval version revolving cannon had been adopted by the Navies of France, Holland, Greece, the United States, Chile, the Argentine Republic, Russia and Denmark. The Royal Navy, however, stuck with the Nordenfelt anti-torpedo boat gun, even after extensive trials in Portsmouth in 1879.
As the torpedo-boat developed in size and speed, the thickness of its plating was increased, and shields added to protect exposed guns. To defeat the more modern torpedo-boats, the Hotchkiss Revolving Cannon was produced in larger calibres, but significantly, the mechanism used was the same in all models. Naval versions with calibres of 47mm (1.85 inch) and 53 mm (2.1 inch) were developed in response. A special version was developed for protecting fortress ditches - this Flank Defence gun fired a 40 mm cartridge.
Advent of the Quick Firing Gun
The increasing size of torpedo-boats, with thicker plating, and often bunkers of coal protecting the vitals (which were generally assumed to be the boilers - put a shell through one of those and the engines stop, and boiler room crews wiped out) meant that a more powerful shell was needed, fired at a greater muzzle velocity than the Revolving Cannons could achieve. Revolving Cannon were also very heavy in the larger calibres and could not be mounted in the fighting tops. New single-barrelled guns were introduced that fired a round that was supplied with the shell, propellant cartridge and means of ignition combined in a single cartridge. These could be loaded and fired quickly - and these guns were designated Quick-Firers (QF). Typical QF guns of the late 1880s were the Hotchkiss and Nordenfelt 6 pounders and as these were light enough to be mounted on the upper decks and fighting tops they rapidly superseded the Revolving Cannon and Nordenfelt machine-guns.
It is likely that the naval and field service Revolving Cannons were removed by the early 1890s, however one variant, the 40mm Flank Defence gun, was retained and several served though the Great War. One revolver in the Fort de Longchamp at Epinal carries out night-time interdiction fire against the advancing Wehrmacht as late as June 1940. It is possible that one of the galleries of the Batterie de l'Éperon north of Nancy is still armed with a pair of revolving Cannon.[H6]
A brief history of the development of the Hotchkiss Revolving Cannon.