semiautomatic vs autoloading

semiautomatic is a noun but autoloading is not a noun.

Word	Noun	Adjective	Verb	Adverb
semiautomatic	Yes	Yes	No	No
autoloading	No	Yes	No	No

As adjectives, semiautomatic and autoloading are synonyms defined as:

semiautomatic and autoloading: (of firearms) capable of automatic loading and firing continuously

Other synonyms of semiautomatic include self-loading.

semiautomatic (noun)	autoloading (noun)
a pistol that is a semiautomatic firearm capable of loading and firing continuously

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