automatic vs shooting iron

automatic and shooting iron both are nouns.

Word	Noun	Adjective	Verb	Adverb
automatic	Yes	Yes	No	No
shooting iron	Yes	No	No	No

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

automatic: a pistol that will keep firing until the ammunition is gone or the trigger is released
shooting iron: a firearm that is held and fired with one hand

Other hypernyms of automatic include automatic firearm, automatic gun, automatic weapon, handgun, pistol, side arm.

automatic (noun)	shooting iron (noun)
self-loading rifle capable of automatic fire	a firearm that is held and fired with one hand
a pistol that will keep firing until the ammunition is gone or the trigger is released

automatic (adjective)	shooting iron (adjective)
operating with minimal human intervention; independent of external control
without volition or conscious control
resembling the unthinking functioning of a machine