Those exposed hammer accidents were more than likely from those Winchester Moderl 94's.
Sisters boy friend years ago had racked a round in the chamber of his and was letting the hammer down, thumb sliped on the hammer and he shot his truck. Neighbour lady had loaded hers in the kitchen and was letting the hammer down when her thumb sliped off the hammer and the round when thru the kitchen ceiling just missing her youngest son sleeping in the bed room above.

al