Wikipedia
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.