P90

The P90 is a compact submachine gun developed and manufactured by Fabrique Nationale de Herstal (FN Herstal). It has an unusual bullpup configuration with a short external barrel and a 50-round magazine that sits on top. It arguably started a new class of personal defense weapons (PDWs) intended to penetrate body armor with small-caliber, high-velocity bullets.[1]

[1]en.wikipedia.org/wiki/FN_P90