By QA/QC, I meant tangible inspection steps like magnetic particle inspection, high pressure testing of components, and adhering to mil-specs. That's why I said most users wouldn't need it because most of us won't push our rifles until failure. If someone would rather have an Olympic Arms, RRA, Bushmaster, or DPMS that has zero handguard movement, so be it, but I wouldn't kid myself into thinking I had the higher-quality rifle. That isn't to say those rifles suck or anything. They still do most of the testing but they batch test rather than doing EVERY rifle and maybe slide on a few of the finer points that probably also don't matter that much.
That said, the S&Ws are high quality rifles as well. They do the majority of the same steps as Colt as far as I know. I think they skip mil-spec on the barrels, but many of them have a nitrided finish which some folks argue is better than chrome-lined.