In 1949, before the advent of Schimel's famous Luger-look-a-like CO2 gun,came a stylish AIR POWERED pistol ,of similar design.It had a multi-stroke pneumatic mechanism with a blow-off "dumper"valve. Advanced advertising had high hopes for this gun but it does not seem to have been marketed commercially. At the time,the factory was into making "custom" guns-maybe the Schimel Model AP-22 ended up in this catagory?

 Schimel "flyer" pages courtesy Dean T Fletcher. Thanks.