The General-purpose machine gun reference article from the English Wikipedia on 24-Jul-2004
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General-purpose machine gun

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The general purpose machine gun (GPMG) is a compromise weapon, capable of doing the tasks of a light machine gun, a medium machine gun and a heavy machine gun, but none as well as a specialised weapon. They generally require the user to be in a prone position to use, being too powerful to fire from the hip. A GPMG is almost always belt-fed.

They are almost all descended directly from the German MG42, which in itself was based on the MG34.