Thanks BCRider. Maybe I'll have to try shooting a few boxes of factory ammo and see how it looks. I don't recall feeling any blowback in my face with the .38, but I did feel an impulse from the .357 magnum (Winchester). I wish I'd saved the brass, each round had a black mark extending from the case mouth about half way down the case in a sort of half-oval, I don't know whether that's normal either.
The Wolf ammo I'm shooting is 158g Lead SWC in what looks to me like a brass case marked Dominion .38 SPL. I took a picture, but my camera died immediately after, so it'll be a while before I can post it (batteries charging...). Magnet won't stick, so I don't think it's plated steel, if that's even a thing anyone does...
A chambered round has a very minute amount of play in the chamber (same as an aluminum A-Zoom snap cap). I have never had any trouble extracting - they don't fall right out like an unfired round when the gun is tipped up, but they've never felt tight either. No additional pressure on the ejector rod is needed compared to ejecting unfired rounds.