Fox was after my chickens one evening. Grabbed an 870 and a few shells, loading on the way out the door. There he stood over a pile of feathers which was, of course, one of my roosters. Threw the gun up. CLICK. Jacked another one in, but that time he was on the run. Got a bang that time but either missed (likely) or the 7.5s I had grabbed were ineffective. Later examination proved the Hoppe's #9 I used to scrub up the trigger group had dried and gummed, slowing down the hammer. The first 'shot' freed it up so the second went off.

The rest of the fox story: A few days later my wife spotted him heading off the neighbor's place, toward the road. I ran across the road with an SKS and waited. Along he came and I lit his world up. As near as I could tell I never hit him, but he hasn't been back.