https://youtu.be/3qElfsloKH8 Walther began developing a modern stamped sheet metal SMG in the late 1950s, and it entered production in 1963. It was an open-bolt, simple blowback gun available in a short (MPK; 6.75” barrel) and long (MPL; 10.25” barrel) version. It was cheap and simple, but well thought out with a number of quite good