I was thinking regular following a squib was unlikely if the shooter obeyed the rules and thoroughly investigated anything unusual, and a squib load is at the least, "unusual" as all hell.
Double charge or wrong powder more likely.
(And for many of this type of video, this old suspicious coot always puts "possible fake" on the table. Maybe, maybe not, but it's there on the table.)
I don't know what they mean by "forcing cone," but I had a real forcing cone split in a Model 19, don't think that would allow the barrel to blow off, but would, rather, jam the barrel in even tighter. Discovered it because its spreading out started to interfere with cylinder rotation. Of course, a possible 100,000 psi in a revolver, any revolver, would thoroughly disperse its parts.
Terry, 230RN