So I was at the gun shop last week and had a good laugh (quietly). An older fellow who didn't seem to be very gun savy brought in a revolver that he was having some issues with. The ammo that he bought was fitting a little tight. His resolution for that was to put a little lube over the cartridges (including the primers) so the revolver would open and close easier. The gun shop worker kindly informed him that he should refrain from putting oil all over the cartridges, or else the gun wouldn't go bang when the trigger was pulled.