Historical Firearms has a good piece on the the Austro-Hungarian Standschutze Hellriegel submachine gun. Apparently this mad bulky water cooled (!) burp gun was developed during 1915 and blended pistol caliber ammunition with the firepower of a machine gun making it one of the first weapons which could be considered an SMG.
When you think SMG, you don’t really think something with the same portability as a Vickers Maxim with 1/10th the range
Dig the assistant gunner waiting patently with the leather and wood frame spare mag carrier
That looks easy to load
