SMG - 5.7x28mm - Belgium - 900 RPM - The P90 was designed as a Personal Defense Weapon (PDW): a compact, yet powerful weapon for heavy weapons crews, radio operators, vehicles crews, etc.  The 5.7mm FN cartridge has amazing armor penetration, yet recoils less than a 9x19mm pistol cartridge.  The unconventional nature of the design has hampered its commercial success. ©D.E. Watters