firing chamber vs gun chamber

firing chamber and gun chamber both are nouns.

Word	Noun	Adjective	Verb	Adverb
firing chamber	Yes	No	No	No
gun chamber	Yes	No	No	No

As nouns, firing chamber and gun chamber are synonyms defined as:

firing chamber and gun chamber: chamber that is the part of a gun that receives the charge

firing chamber (noun)	gun chamber (noun)
chamber that is the part of a gun that receives the charge	chamber that is the part of a gun that receives the charge