Ah I was just pulling your leg with the "chuffed" comment.

Getting back to the sounds of silence... Merriam-Webster gives one definition of silence as a transitive verb meaning "to cause to cease hostile firing or criticism," which is how it is being used in the sentence in question. And "gunfire" is being used as a type of synecdoche or metonymy as Faldage pointed out. What I find objectionable (mildly) is that "largely silenced" is a bit like "mostly a virgin" or "a little bit pregnant."