As you move the barrel release, you hear the "click" just as the barrel release reaches its full open position (or maybe just a hair before it reaches full open), the release stays open. The trip spring hanging sounds like a likely culprit as it popping up would be consistent with a clicking sound. My other thought was maybe the gun was too tight? and its the hinge pin clicking as the barrels want to pop open? I'm thinking no matter what it is, its probably a good idea to have someone more knowledgeable look it over, so i'll probably send it in... I will let you know what it turns out to be..