searching fire vs firing

searching fire and firing both are nouns.

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

As nouns, firing is a hypernym of searching fire; that is, firing is a word with a broader meaning than searching fire:

searching fire: fire distributed in depth by successive changes in the elevation of the gun
firing: the act of firing weapons or artillery at an enemy

Other hypernyms of searching fire include fire.

searching fire (noun)	firing (noun)
fire distributed in depth by successive changes in the elevation of the gun	the act of setting something on fire
	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