firing vs barrage fire

firing and barrage fire both are nouns.

Word	Noun	Adjective	Verb	Adverb
firing	Yes	No	No	No
barrage fire	Yes	No	No	No

As nouns, barrage fire is a hyponym of firing; that is, barrage fire is a word with a more specific, narrower meaning than firing:

firing: the act of firing weapons or artillery at an enemy
barrage fire: the heavy fire of artillery to saturate an area rather than hit a specific target

firing (noun)	barrage fire (noun)
the act of setting something on fire	the heavy fire of artillery to saturate an area rather than hit a specific target
the termination of someone's employment (leaving them free to depart)
the act of discharging a gun
the act of firing weapons or artillery at an enemy