My 8 gauge does that with the 8-12 gauge mates

Gremlins.

Ringing noise
 

I had a 2 frame 12 ga Trojan, and a 12 guage Sterlingworth that rang upon firing. I am not a physicist, but would guess that the ringing is related to harmonics. A vibration that results from strong springs, creating an audible ringing noise. Sort of like a tuning fork. I don't think it is indicative of any problem. Both the Trojan and Sterlingworth performed flawlessly in a variety of conditions, and over a long period of time. Just my thoughts.

Recoil, torque and internal stock wood bearing on metal parts. Browning O/Us, which I owned and shot in competition for many years, (mostly 12 gauges), would exhibit this identical phenomenon. In the case of the Browning and other O/Us, FN gunsmiths claimed that because of the angle of the firing pins, one or the other (over or under) pins within their springs would have adequate room to vibrate the springs upon detonation, causing the wave of vibration to travel to the barrels and "release", so to speak, upon the vent rib or along the forend iron.

This produced the familiar "singing sound" heard upon shooting, which lingered for a few hundredths of a second after firing. The theory being that either one side or the other of the firing pin race and spring alignment of a SxS, or the upper or lower barrel of an O/U, was "tight" or "loose" in terms of transmitting the tuning-fork-type sound as described.

Particularly rapid firing in succession, as in skeet doubles or in bunker trap, would cause a dampening effect on the first detonation as the gun recoiled, thus attenuating the vibration upon the first shot, but allowing a lingering tone on the second shot, clearly audible as a "ringing" sound".

According to harmonic physics, the higher the quality of the steel, the more "finely tuned" was the ringing sound perceived, due to the more even transmission of the sound waves along the straighter lines of laminar flow of the higher quality steel.

We should all read Mr. Travinsky's original post wherein he specifically states that he hasn't experienced this phenomenon with live ammo.... But that it is really loud when he uses snap caps.

I dry fired my 1-1/2 frame VH12 yesterday when I was ready to put it away and when I fired the left bbl the gun rang like a bell. I think the hammer hits the frame when there is no shell in it and just triggers a resonance when all factors are just right. If the hammer had hit a firing pin it wouldn't hit the frame, if I have my vision of the internals correct. I've never really noticed it before but I v rarely dry fire them. This one sure rang with a good high-frequency tone of relatively short duration.

My #2 frame Trojan also rings when dry fired. I've shot it a ton but never paid any attention to see if rang with live ammo though. But that said, never had a problem with it either, so I generally don't think to much about it.

I have a two frame Trojan that rings when it is dry fired or fired. I have a 1 1/2 frame VH that rings so loud I could hear it over the bang of the shell going off. The ringing guns have become much quieter as I have grown older...................

new to owning a Parker and have a big GHE #2 frame that rings with both barrels, snap caps and live shells. I'd like to have it eliminated if anyone knew for sure how to do it.

Some guns do it, some dont. It is a matter of resonance in the frame.

I had an A grade in the shop recently that rang the loudest I had ever heard. It was very loud on the one barrel.
Part of my work was a full strip and clean. Along with a bunch of stock work. When I was done, it did not do it anymore. But I did not do anything specifically to address it or find out the cause.