assault rifle vs machine rifle

assault rifle and machine rifle both are nouns.

Word	Noun	Adjective	Verb	Adverb
assault rifle	Yes	No	No	No
machine rifle	Yes	No	No	No

As nouns, machine rifle is a hypernym of assault rifle; that is, machine rifle is a word with a broader meaning than assault rifle:

assault rifle: any of the automatic rifles or semiautomatic rifles with large magazines designed for military use
machine rifle: self-loading rifle capable of automatic fire

Other hypernyms of assault rifle include automatic, automatic rifle.

assault rifle (noun)	machine rifle (noun)
any of the automatic rifles or semiautomatic rifles with large magazines designed for military use	self-loading rifle capable of automatic fire