delayed blowback vs retarded blowback

delayed blowback and retarded blowback both are nouns.

Word	Noun	Adjective	Verb	Adverb
delayed blowback	Yes	No	No	No
retarded blowback	Yes	No	No	No

As nouns, delayed blowback and retarded blowback are synonyms defined as:

delayed blowback and retarded blowback: A type of firearms operating system which requires the bolt to overcome some initial resistance while not fully locked.

delayed blowback (noun)	retarded blowback (noun)
A type of firearms operating system which requires the bolt to overcome some initial resistance while not fully locked.	A type of firearms operating system which requires the bolt to overcome some initial resistance while not fully locked.