Earlier quoted context omitted.
https://en.wikipedia.org/wiki/Philip_Luty#Firearms_design > one particular design, outlined in his book Expedient Homemade Firearms, is the best known. This design makes extensive use of easily procured materials such as folded sheet metal, bar stock, washers, and hex screws. It is a simple blowback-operated sub-machine gun and entirely made from craft-produced components, including the magazine and pistol grip. The…
See it in action: https://www.youtube.com/watch?v=3YE9J7qcj0c
Oh well.