CLEARING THE ACTION IS NOT ENOUGH
You can rack the slide, lever, pump, bolt all day and still have a round in the gun, if you have a bad extractor or the round remains somewhere in the action/receiver. You may just simply not see something or "see" what you expect/want to see. At a steel challenge a week ago after shooting my round, (Ruger 1022) the RO says open the action & show clear, I do, He looks & says "I see clear", I look and say "I see clear" We both only looked at the empty chamber & missed the live round hiding in the receiver, which I felt with my pinky finger after. We both felt foolish. the Moral is to STILL use the other principals of safe gun handling as a redundancy. Keep the muzzle pointed in a safe direction & your finger off the trigger. To the original ? I check every gun going in/out of the safe, holster, case, range bag. My nightstand gun stays fully loaded at all times in a holster