Troubleshoot a long-gone gun?
Many years ago, we had a bolt-action .22 with a tubular magazine. I believe it was a Wards "Western Field".
We sold it (with full disclosure, of course) after it developed a malfunction. Opening the bolt and chambering a new round would cock the firing mechanism as normal, but as you closed the bolt on the new round, it would "de-cock" itself. It wouldn't spontaneously discharge or anything like that - it just looked/felt like the firing pin was slowly moving forward to the "fired" position as you closed the bolt.
I'm just curious now as to what the nature of the malfunction was. Does this sound like anything obvious to any of you?