mg42
Developed in 1939, the MG42 replaced the MG34 in 1942 as the Nazi Germany's Wehrmacht main general purpose machine gun, taking over the roles of both light and medium machine-guns.
The MG42 was versatile, used to great effect in bunkers and on vehicles, and had an impressive rate of fire at 1200 RPM.
However, its rate of fire far exceeded its cooling capability meaning it quickly overheats after a few seconds firing. The gun's basic design is still used in the Bundeswehr's MG3 and in other armies, and served as basis for the design of many modern light machine guns like the M60.