Interesting was a comment on the page talking about the chainfire and the person that posted the vid said it was because he "didn't use enough grease". In all the time and years I've shot C&B, it occurred to me I've never had a chainfire with an open top, when using a proper fitting bullet. On the other hand I've had a few on the Remington design. I got my Lyman (ASP) NMA .44 in the late 70's and shot the bejeezus out of that thing. I would shoot until it wouldn't turn anymore and I had to hammer the cylinder pin out, then do it all over again.
In all that time I probably had 3 or 4 instances of a chain detonation, always a chamber to the left of the bore. I mentally attributed it to a stray cap fragment that bounced just right, but some people say it can be caused by strong flash from the fired nipple jumping over. I dunno. But so long as I am using correct, chamber mouth sealing bullets in an open top, I can't remember a single instance of that happening in that design. Maybe I'm lucky, or need to shoot more.