Actually what we have here is prime example of a) Angels often protect foolish people, and for other folks b) this is why evolution takes soooo long, because not every really stupid, potentially lethal act results in a lethal result with the person taking the action.
Here's How He Survived:
First, he got lucky that he chose
Clays, because that's a very popular powder for the folks doing Cowboy Action Shooting, and it and
Universal give them the lowest chamber pressures in many cartridge handgun loads.. He merely looked at the label, and thinks "Gee the .44 special is similar"..., well no it's not really, since
his handgun is called a .44 but in fact shoots, .451 or .454 projectiles, not .429 projectiles. He references 165 grain bullets, too, BUT, he's launching 138 grain, .451 round ball (you can see it on the bullet box label if you hit pause right), which is lighter than the data he thinks is "close" AND has a lot less friction against the chamber walls than would a 165 grain .451, conical bullet. Perhaps he thinks that since the conversion cylinders for using .45 Colt will work with smokeless "CAS Loads" or black powder, then why not the original cylinder ??
Of course the conversion cylinder instructions tell users to use either specific factory loads, or black powder cartridges. Now those cylinders are not the same steel as that which comes with the repro revolver, but pyrodex loads show they should hold at least 7,600 CUP and probably a bit higher. So what the "talent" in the video did was use a light load, with a lighter than documented bullet which also had less friction, and thus probably came in under 6000 CUP, so succeeded
so far, in not blowing himself up..., especially using that really consistent powder measure. Now if he used a different powder, or if some poor slob watched that dumb-arsed video and used the wrong powder, or HECK, if the user was distracted and dumped two loads of the "safe" smokeless powder into a chamber instead of the one....
BOOM ! And the user will have a new nickname of "Lefty".
LD