Where the guy has a blowtorch and is waving the torch flame over the cylinder to prove that chain fires are from loose percussion caps (like Elmer Keith said) and not from the flash jumping from one cylinder to another. Remember, an oversized ball shaves a ring which tells the user that the cylinder is sealed.
Anyway, I couldn't find it but I did find some guy who shot his cold underwater. This is one of those, "Don't try this at home kids."
https://youtu.be/NEGdt9KXcbI