The resulting design was a highly distinctive blowback-operated downward-ejecting bullpup SMG with an overhead magazine based on the mechanism of the Heckler & Koch G11: rather than replicating the complex rotating breech of HK's weapon, however, the P90 instead features a spiral feed ramp integral to the magazine, which rotates the left-facing rounds to align with the breech. The FN P90 is a compact submachine gun designed by FN Herstal in response to a NATO request for a light armor-piercing round to replace the 9x19mm Parabellum as the standardized pistol and SMG cartridge, along with a compact 'personal defence weapon' similar to the AKS-74U to fire it.
