BAR vs automatic rifle

BAR and automatic rifle both are nouns.

Word	Noun	Adjective	Verb	Adverb
BAR	Yes	No	No	No
automatic rifle	Yes	No	No	No

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

BAR: a portable .30 caliber automatic rifle operated by gas pressure and fed by cartridges from a magazine; used by United States troops in World War I and in World War II and in the Korean War
automatic rifle: self-loading rifle capable of automatic fire

Other hypernyms of BAR include automatic, machine rifle.

BAR (noun)	automatic rifle (noun)
a portable .30 caliber automatic rifle operated by gas pressure and fed by cartridges from a magazine; used by United States troops in World War I and in World War II and in the Korean War	self-loading rifle capable of automatic fire