machine rifle vs BAR

machine rifle and BAR both are nouns.

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

As nouns, BAR is a hyponym of machine rifle; that is, BAR is a word with a more specific, narrower meaning than machine rifle:

machine rifle: self-loading rifle capable of automatic fire
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

Other hyponyms of machine rifle include assault gun, assault rifle, Browning automatic rifle.

machine rifle (noun)	BAR (noun)
self-loading rifle capable of automatic fire	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