I was at work the other day and had my soft black leather brief case with me. I picked it up to move to another room, and heard behind me a deep clink, tink, tinka tink.... My co-worker, who is into shooting as well, asked me what fell out of my bag. I told him that, by all sounds of it, I'd had a .45 acp case drop out of my case. I don't have a CLUE how it got there, and because I had just had a day of shooting .45, 9mm, .40, .308, adn .223, even if I'd been sure of how the brass had gotten into my bag, it could have been any of those cases. But, as I'm sure most of you know, .45 acp cases have a particular clink about them.
I spent the next 2 or 3 minutes looking for it, and finally found it under an open door against the wall. My friend was surprised that I KNEW what it had been, without seeing it (there were no other cases in my briefcase). But what else sounds quite like that?
The big hammer on a big old Colt Walker has quite a resonate sound to it.
The rack of an 870 is utterly classic.
The combined sound of a 1911's loading or unloading is a classic sound to me.
The ascending pitch of a tight bronze brush being pushed through a rifle barrel is a favorite sound of mine.
There's plenty more.