But Wonko... traditional lore trumps empirical observation every time.
The only time I've heard barrels ring, actually a fairly low pitch vibration, is when some idiot slams a gun shut. It sounds a tad like a diving board.
I attribute it to a cry of pain.
word !
Actually I've had three guns that made a ringing sound when fired. A member of the club I belonged to at the time had one as well and he called it a "singer". The ones I had were two 682 Berettas and a Perazzi MT6 with barrels too long to bother keeping so I have none of the three now. I found the sound irritating enough to justify flipping the lot. I did some serious searching trying to find the source of the ringing and never did find a way to eliminate it. All three are coil spring hammers tho so there is no rebounding element like a leaf spring usually has. I decided that the ringing was from the hammers striking the action. I didn't really try to test that at the time since it was easier to just get rid of them.
But some guns do "sing" for sure. Been there, done that.