The original concept of this video was as follows:
To see if materials salvaged/found could be used to make ammunition work in a last ditch effort such as swept up unburnt powder, scrap powder from the floor of a workshop, scrap bullets, etc.
To see if an over pressure .454 would explode the gun (which they did)
To see what would cause a .410 Shotgun to explode.
We concluded the following:
A .410 Shotgun of reasonably good quality is probably one of the most useful firearms to have around. It will feasibly fire .410 shotshells, .44 magnum, .454 Casull, .30-30 WIN, and others without damage in most cases. We are not advocating you do that.
.410 Shotguns can take a significant amount of pressure before failing. We measured the bore for deformation and none resulted. The barrel to action tightness was not affected.
Some very powerful "loads" were discovered by using .454 Causull, .44 magnum, .444 Marlin, etc. A .454 coming from a .410 barrel will kill anything on the North American continent within 15 yards in a pinch.
A .454 Casull magnum exiting a .410 barrel would most definitely kill a human being in one shot. Considerably more kinetic energy than even the most powerful .410 shotshell.
Range "scrap" powders should not be used as a propellent unless deemed absolutely necessary.
These experiments were conducted from a safe distance with proper protocols being followed. A medic was on hand.
Do not try any of these experiments on your own.