Heavy machine gun
Heavy machine gun is a term used to describe automatic firearms which are of 7.62mm or 30 caliber or higher. The rounds fired by a heavy machine gun range in size from 7.62mm x 51mm, up to the 50 cal, which is 12.7mm x 99mm. The Russians have a 14.5mm caliber machine gun. However, traditionally the term heavy machine gun is used only for 50 cal.