Fokker - Leimberger The Fokker - Leimberger was an externally powered , 12 - barrel rifle - caliber rotary cannon developed in Germany during the First World War . The action of the Fokker - Leimberger was fairly different from a Gatling though , employing a rotary split - breech design , also known as a " nutcracker " . Fokker claimed the gun achieved over 7200 rpm , although this may be an exaggeration . Failures during the war were attributed to the poor quality of German wartime ammunition , although the type of breech employed had ruptured - case problems in a British 1950s experimental weapon . Fokker continued to experiment with this type of breech after his post - war move to the United States . A different Fokker prototype in a US museum basically attests to the failure of this line of development . Design . The Fokker - Leimberger used a rotary split - breech design known as the " nutcracker " . In this design a temporary chamber is formed by joining the two cavities of touching , counter - rotating sprocket s . The simplicity of the design was appealing , particularly because it contained no major parts using a reciprocating motion , like the breechblock used in many other automatic weapons . Ignoring the various material stresses , the maximum rate of fire was thus theoretically limited only by the time needed to complete the burning of the propellant from each cartridge . Anthony Williams commented on this design that : " Fokker claimed that 7 , 200 rpm was achieved , but knowing Fokker , there is some reason to assume that that may have been slightly exaggerated . Problems occurred , of course , with cases bursting on the seam between the two cylinders . " Another " Fokker Split Breech Rotary Machine Gun , ca . 1930 " was donated by Val Forgett to Kentucky Military Treasures in 1977 ; according to the museum record it " proved unsuccessful because of its inability to seal breech cylinders " . The British also experimented with this type of breech for aircraft guns in the 1950s , but abandoned it . This type of breech has only been used successfully in low - pressure applications , such as the Mk 18 Mod 0 grenade launcher . The Fokker - Leimberger used percussion ignition with the firing pins mounted on a swashplate . No extractor was employed ; the spent cases were simply left on the outgoing belt . The gun would have had to be pre - rotated in flight in order to ensure that when the trigger was pulled it would have fired at its maximum speed at once . Similarly to the Gatling designs , the use of multiple barrels enabled air cooling of each barrel in the time between successive shots were fired from the same barrel . History . The development program that lead to the Fokker - Leimberger prototype was apparently initiated by the Idflieg through a circular sent to German firearms manufacturers on 16 August 1916 . This document , authored by major Wilhelm Siegert requested lightweight designs with a high rate of fire for use in German aircraft . It also suggested that external power sources be used for the automatic firing , like the aircraft engine itself or electrical power . The circular was answered by designs from various German companies . Besides Fokker , Siemens , Autogen and Szakats - Gotha also submitted proposals . None of these entered mass production before the war ended , although the Siemens prototype was used on the Western front and claimed one aerial victory . As with his other machine - gun - related designs , Fokker collaborated with Heinrich W . Lübbe and with another engineer named Leimberger for this project . Initially they developed a simple adaptation of the Maxim action ( itself widely used in Germany in the MG 08 ) , driven by a crank from the engine . Their more ambitious project however employed the yet unproven split - breech action , in a 12 - barrel design . The idea for this type of breech was not entirely new , having been patented in the US as early as 1861 ( USPTO # 32 , 316 ) . ( Other US patents from the early 1920s indicate there was renewed experimentation with this design in the US as well . ) No record survives for the gun ' s ballistic performance , beside the claim for over 7 , 200 rounds per minute . However , problems with ammunition were recorded , as " only too often the cases tore open in the gun " . After the war , a Fokker - Leimberger prototype was claimed as personal property by A . H . G . Fokker , and he took it with him when he emigrated to the US in 1922 . The donation record for the exemplar now found at the Kentucky Historical Society states that all other exemplars were destroyed .