Regarding the reference to Glock's use of MIM, if I'm not mistaken they did in fact have some issues with MIM parts. Kimber did as well.
I don't have specific knowledge of the issues with glock or kimber parts. I suspect though, that it was an engineering or design flaw, rather than a flaw with the MIM process. A poorly engineered part cannot be saved by any forming process.
And there can be and are issues with the MIM process. But standard QA procedures are real good at catching them before they leave the facility where they are made.
The MIM process is so exact that a simple part weight indicates quality very well. Ultra sonic inspection is nearly infallible.
QA is not a free service though. It costs, and cost can be an issue in modern manufacturing.
