KWA KZ.61 (Vz61) Scorpion Gas blowback SMGKWA KZ. 61 (Vz61) Scorpion Gas blowback SMG KWA Gas Blowback Scorpion with 20rd Magazine. Development of the vz. 61 Skorpion was initiated in the late 1950s, with the intent to provide various non infantry units with a lightweight, personal defence weapon that brought more firepower than the standard pistol. First prototypes of the new weapon were built in 1959 and was officially adopted by the Czech Army in 1961. Although the vz. 61 Skorpion was