semiautomatic vs shooting iron

semiautomatic and shooting iron both are nouns.

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

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

semiautomatic: a pistol that is a semiautomatic firearm capable of loading and firing continuously
shooting iron: a firearm that is held and fired with one hand

Other hypernyms of semiautomatic include handgun, pistol, side arm, semiautomatic firearm.

semiautomatic (noun)	shooting iron (noun)
a pistol that is a semiautomatic firearm capable of loading and firing continuously	a firearm that is held and fired with one hand

semiautomatic (adjective)	shooting iron (adjective)
(of firearms) capable of automatic loading and firing continuously
partially automatic