I had that happen to me once back in High School shooting my newly acquired 1860 Remington. I forgot to lube over and had two barrels go off. Fortunately not the bottom one behind the frame. I never used anything other than lube, but I understand wads with lube is better. A good friend of mine, a while back, bought him one and he was going to use it on some feral cats that kept coming into his yard. We lived in a small town and were both on the outskirts of town. He drew down on the critter at about 15 yards, pulled the trigger and had 4 chambers go off. He apparently didn't lube any of them. Funny thing, was when the smoke cleared, he said that the cat was still standing there.