Evry now and then we have all experianced a chain fire when firing our revolvers, either with Blanks or live-fire. I have noticed that this happens most often when firing blanks.
The last time I saw it, I was at the local range with a friend and he ask to fire my Remington 1858 .44. I handed him the revolver empty and he had to load it. He did so and did not grease the cylinder mouths. On his second shot he yelled and I ask him why. I had heard what sounded like an over charge ( he is good at that) . He then showed me where the second ball had left the the bottom chamber that was just outside the frame and skidded along the metal. No damage was done and he was not hurt. He did learn to grease each chamber.
I reading and action I found that if I get a slighlty oversized ball and load it, it shaves off a ring of lead as it seats. I have never had a chain fire when the cylinder is loaded in this way.
When loading a cylinder, reloading in particula, we all sometimes spill a bit of powder on the cylinder face and if there is grease from the last rounds, the powder is not that easy to remove, so we go on loading. Even with new grease over the powder and a slightly loose ball, the flame from the burning powder can pass the ball in the chamber and get to the powder on the cylinder face and travel to the next chamber and set it off.
With a tigh ball, the flame can not pass the ball in the chamber being fired and it can not then get to the next chamber and cause it to fire. Just as the rings on an engine piton seal the gas in the upper part of an engine cylinder. for full combustion, the tight ball does the same thing and seals the chambers. Thusly, the grease is then just a redundant safety measure (still a very good idea). try this the next time you live fire ot load up some powder, cream of wheat and grease and see if you maybe dont come to this same conclusion.
Opinion expressed is in no way the Moderators, just IMHO