I have never had a rifle problem interfere with a shooting opportunity. I see there is some lattitude being taken in answering, however, so I'll mention a few hang-ups I've experienced that were benign.

I had my sling release my rifle and the barrel hit the ground as a result (operator error attaching the sling in the dark). I swapped this out for an alternative rifle that was handy to hunt with that day. I checked the barrel out that night, cleaned the barrel out of abundance of caution, no harm done to rifle (it was a pretty gentle hitting of the ground, cause I caught the rifle as it was coming free).

I had a bolt on a Springfield action come open and jack the unfired .25-06 round out onto the ground. After that I keep my arm sort of locked over the bolt to prevent it sweeping open.

I have had rounds not feed into my .30-06 Springfield on reloading at the rifle range. Glad I wasn't facing down a bear charge. This is a rare happening, but it has happened more than once.