I had an incident with my 6 month old Browning XS Skeet today. When I pulled the trigger the firing pin didn't fall.
I opened it, removed the good round, replaced it, closed it and switched the barrel selector from under to over and back to under. It fired and I had no more trouble shooting 100 shots, if we forget the misses.
I figure the problem was that when I got to the range, I fired a round of Remington home defense ammo from which I had removed the shot. I only dis so to dispose of the powder and discharge the primer before trashingit. While it had enough oomph to eject the wad from the barrel, I expect it somehow got the inertia trigger transfer hoop dee doo system convused.