This article will examine what is known about a prototype revolver developed by pre-state defense organizations and the industrial group Ta’as in collaboration. This project started in the 1940s as an effort to design and produce a sidearm using the ubiquitous 9×19mm Parabellum cartridge. The proliferation of Sten guns throughout the region meant a sidearm of the same caliber would simplify logistics significantly for the Jewish underground. 9mm Parabellum was also readily produced in pre-state Israel (prior to 1948 in a covert operation that included the Ayalon Institute) so it was a logical choice in caliber.