Mg3

The MG3 is a German general purpose machine-gun being the earlier MG42 (MG1 or MG2) further redesigned during 1968 to accept either the German belt or NATO disintegrating link belt, and later a 150 round belt drum magazine.
Found on http://www.probertencyclopaedia.com/browse/FMM.HTM

MG3

(from the article `MG42`) ...German army after its modification in calibre; guns that had been reworked from the old to the new calibre were then called MG2, and a further ...
Found on http://www.britannica.com/eb/a-z/m/83
No exact match found