[Mobhack]

An "HMG" in one army might be a 50 cal, in another it may be a jacketed water cooled MMG, or just a rifle calibre weapon.

You takes your army and whatever designation they give it (or whatever the OOB designer used perhaps based on his nationality) for a tripod MG, really.

Personally I prefer the British (NATO?) designation of "Sustained Fire Machine Gun (SFMG)" for any belt fed tripod mounted weapon, as it ignores calibre, water jackets or whatever Army A uses as against army B, to designate these.

Andy