The Parabellum MG14 air-cooled machine gun in 8x57mm IS was the standard machine gun used on trainable mountings aboard German aircraft of World War 1 (1914-1918). It was essentially the classic water-cooled Maxim 1908, evolved through the air-cooled MG08, and made its presence known throughout the conflict while the MG08 was primarily used as the fixed gun emplacement at the nose of many aircraft. As serviceable a gun as there was, the Germans sought a new weapon with a higher rate-of-fire as the MG14 managed just 600 to 700 rounds-per-minute. This requirement was solved in one way by the development of one of the most unique weapons to come out of the Great War - the "Gast-Maschinengewehr Modell 1917" - or "Gast Gun".
Design work began in secret during 1915 by Carl Gast (as part of Vorwerk Company) and his creation was just one of several under consideration by the German Air Service at the time. In Gast Gun, the issue of high rate-of-fire was solved by providing a dual, side-by-side barrel arrangement. The recoil-operated action was such that the movement of one of the barrels powered the feed system of the other in succession, allowing the weapon to fire off bullets in rapid fashion. To content with the rapid exhaustion of ammunition, each barrel of the gun was fed by its own drum magazine holding 180 to 192 ready-to-fire 7.92mm cartridges (the same used by German riflemen). The drums were set vertically along the sides of the weapon. To simplify operation, a single trigger unit was used by the firer (set near a traditional pistol grip handle) and the wooden shoulder stock was hollowed out to save weight.
The rate-of-fire possible with this machine gun reached 1,600 rounds-per-minute - over double what the MG14 was capable of . Muzzle velocity was rated at 3,100 feet-per-second and effective range was out to 2,000 yards.
Patents for the function of the Gast-Gun were secured during 1916 and 1917 as nothing like it had ever been witnessed.
The first viable example of the Gast Gun appeared in mid-1917 and development spanned into early 1918 when official testing was begun. The tests overwhelmed German authorities who optimistically called for several thousand examples from a first-batch. This continued into late in the year though, by mid-November, the war was over and German found itself on the losing side. It was only in the post-war period that the gun was even made known to the Allies (kept under wraps by Germany until 1921) who promptly snatched up samples and tested it at length in their respective countries. The machine guns were found to be excellent weapons in terms of reliability, durability, and function despite the many moving parts. However, the post-war drawdown worked against this rather novel and expensive design which did little to improve upon tried-and-proven machine guns already in vast circulation.
As such, no one world power pushed to adopt the system and it ultimately fell to history. The Gast concept did live on a time longer, however, when it influenced the Soviet GSh-23L automatic cannon for installation in fighting aircraft.