Can a pistol really handle that kinda stress, long term? The thing has got to fall apart after a use or two.
Depending on what materials the frame is made out of you could see cracking on the crane, just south of the forcing cone. As an example S&W's new models have been reported to crack, in the above mentioned spot, for rounds that produce higher pressure (magnum, +p). That's because S&W started using an alloy to make the revolvers lighter.
The Super Warhawk is based off of the
Ruger Super Redhawk (the Super Blackhawk is a single action hunting revolver so I don't think it based off of that model). Revolvers are heavy duty and simple in mechanics, but they are engineered to fire whatever they've been chambered for. In this case the Redhawk is based off an 'N' frame, which is designed to shoot hunting sized calibers, like the .44 Magnum/.454 Casull. So ultimately the GM needs to decide if the High Power Chambering is scaled up beyond what the frame is designed to shoot. IRL the Redhawk is already at the top end of what the frame can handle, but who knows what it's designed to do in the Warhawk.
I would make the call that they would need a frame rebuild to handle the scaling up in ammo (the whole point of the Ruger Super series is to handle the largest caliber round for the largest frame). Another example would be like trying to modernize a .45 ACP cartridge from black powder standards, which is where it is still IRL, to current capabilities. The pistol would have a catastrophic failure in your face if you fired it without a total rebuild to handle the new characteristics. The cylinder I wouldn't worry about as much, because they are designed for HIGH pressures, but I still wouldn't fire it under water (there was only ever one revolver designed to fire under water and it wasn't a mainstream weapon).