A 5.7x28mm Handgun made by Fabrique Nationale, it fires the same ammunition as the Sun Machine gun version, the FN P90, shooting the Sub Sonic Armour Piercing round, it is capable of penetrating a Kevlar vest at some 300 meters.
Designed as the sidearm to accompany the P90 PDW, the Five-seveN pistol by Fabrique Nationale uses the same 5.7 x 28 mm cartridge as the P90. Despite the bulky nature of the ammo, the 20-round magazine can still be fitted into a comfortably-sized grip. The pistol itself was originally a striker-fired double-action only one, although the "tactical" version introduced a single-action mechanism. Operating by the traditional Browning breech-lock method, the Five-seveN has very little recoil for a combat pistol, rougly 2/3 of a gun of equal bulk in 9 mm Parabellum. With a muzzle velocity of 2100 ft/sec, the Five-seveN is just as capable of piercing armor as the P90. And the capitalization of the N in "seveN" is undoubtedly a marketing gimmick on the part of FN.