Ian looks at this lesser known SMG by Walther made in 1960s.
https://www.youtube.com/watch?v=tQSilZnqdlA
You can also see similar coverage by The Firearm Blog with the same gun
http://www.thefirearmblog.com/blog/2015/02/05/tfbtv-walther-mpl-smg/
From: Forgotten Weapons