Description from first MP38 manual “Beschreibung der Maschinenpistole 38 (M.P.38)”
Description from first MP38 manual “Beschreibung der Maschinenpistole 38 (M.P.38)”
The first official publication in which the MP38 carrying sling was described and pictured was the “Beschreibung der Maschinenpistole 38 (M.P.38)”. On page 11 of this manual the carrying sling is described as follows:

a) Carrying sling
The carrying sling is held to the weapon at the front by a clamp and at the rear by a sling loop with knob through a slot in the grip. The clamp makes it possible to lengthen the carrying sling.

Exactly the same text is used in the succeeding D167/1 manual; “Maschinenpistole 40 Beschreibung, handhabungs- und Behandlungsanleitung”.