In 1936 or 1937, the BSW company (Berlin-Suhler Waffenwerk) produced a small number of prototype pistols for German Army trials. These trials were eventually won by the Walther P38, and for good reason in this case. The pistol BSW submitted was a gas-accellerated blowback design, with an aluminum frame, stamped slide, 13-round magazine (in 9x19), and double-action-only shrouded-hammer firing mechanism.
I had the opportunity to try shooting one of the 3 surviving examples of this pistol thanks to the generosity of a reader named Steve (thanks, Steve!). This is one of those cases where it seems that the trials board evaluating guns made the right conclusion - this pistol was finicky to disassemble, quite large, and had harsher than normal recoil because of its light weight, high bore axis, and blowback mechanism. Its 13-round magazine was a nice touch, but one of very few positive elements in the gun.