<P> The P90 and its 5.7 × 28mm ammunition were developed by FN Herstal in response to NATO requests for a replacement for the 9 × 19mm Parabellum cartridge and associated pistols and submachine guns . NATO called for two types of weapons chambered for a new cartridge -- one a shoulder - fired weapon , and the other a handheld weapon . According to NATO , these new weapons , termed personal defense weapons ( PDWs ) , were to provide `` personal protection in last - resort situations when the user is directly endangered by the enemy ( ... ) . '' In 1989 , NATO published document D / 296 , outlining a number of preliminary specifications for these weapons : </P>
<P> The P90 and its 5.7 × 28mm ammunition were developed by FN Herstal in response to NATO requests for a replacement for the 9 × 19mm Parabellum cartridge and associated pistols and submachine guns . NATO called for two types of weapons chambered for a new cartridge -- one a shoulder - fired weapon , and the other a handheld weapon . According to NATO , these new weapons , termed personal defense weapons ( PDWs ) , were to provide `` personal protection in last - resort situations when the user is directly endangered by the enemy ( ... ) . '' In 1989 , NATO published document D / 296 , outlining a number of preliminary specifications for these weapons : </P>
what kind of ammo does a p90 use
what kind of ammo does a p90 use
5.7 × 28mm
5.7 × 28mm