I don't have a background in metallurgy, but have been told by a 'smith with mech engineering background that case coloring, done properly, is only "skin deep" and doesn't alter the metal beneath it. So it shouldn't weaken any receiver or action that is colored.
Still looks lousy on bolt actions IMO.
And on other types of actions that are not traditional. I bought a case-colored G2 action from T-C's Custom Shop when they were offering them, hoping that a "traditional" finish would help make a G2 Carbine look more like a proper single shot rifle instead of the ugly hybrid it is.
It didn't. The thing still shot like a house afire and switched barrels and calibers slick as snot. And still looked BUTT UGLY. Soon traded it off for 2 more barrels for my (admittedly and frankly) ugly blued G2s.....
