Gordo, you asked:
Wonder what kinda trash metal cant take "muzzle gases"?
It's not "trash metal", but barrels are made of a very high-grade steel, that can stand up to thousands of rounds of bullets pushing their way through the rifling, superhot propellant gases following the bullet, etc. Their steel is of a special grade, which will stand up to this abuse. The frame of a firearm is NOT made from the same steel, as it doesn't have to take that kind of abuse.
A good example of this is to look inside the top of the frame of a .357 Magnum revolver that has fired a lot of full-power ammunition, particularly the 125gr. "quickies". You'll find a "flame-cut" just above the forcing cone, where the gases have cut into the top strap. The barrel won't suffer the same damage - it's a different, harder steel. This flame-cutting is the main reason why S&W went to the L frame for their .357 service revolvers, and Ruger did the same, going from the Security-Six to the GP100. The bigger guns have more metal on the top strap, and can better handle this sort of punishment.
So it's not "trash metal" - just a different kind of steel, perfectly adequate for its job. However, that job is NOT to stand up to thousands of rounds worth of propellant gases in close contact!
JohnK - check out new-production Redhawks. The trigger is vastly improved from earlier models, so much so that I don't know if a trigger job would be needed at all for double-action shooting. I don't know what Ruger's done with them, but whatever it is, I like it!