Too bad we don't have a sticky on this issue, with evidence or names and dates, to send to Ruger. Anecdotal posts don't have the same effect.
Remember Ruger is moving to a "parts bin" assembly gun model and shedding all their "fitted parts" fitted-guns production model. Wait till this impacts the No 1 and shotguns!
It's not about MIM at all, it is the dimensional check (or rather lack thereof) and the force required to set the front sight that fractures the part upon assembly. Then its just a matter of time/cycles before it fails.
The assembly lot was identified long ago by Ruger as a supplied-part problem and allegedly corrected. (despite a request I was not ever provided with any RCCA documentation, internal, supplier or otherwise).
Still, a heckuva lot better response than Springfield's issue a few years back, with their SS 1911 going FA out-of-the-box!