Basically, exactly what the title says. I know how to tell if the case has been over annealed, and I get it that everyone says that it's bad, but what--exactly--is the problem that over annealing causes?
It takes a bit to over anneal but basically it jut gets so soft that it won’t provide proper tension on the bullet which can lead to inconsistent ignition etc.
We try to hit 750 degrees as fast as we can so that the bottom of the case stays hard so it can avoid deformation from pressure but so that the neck of the case softens down to the levels you see. Keep going too much and you reset too much of the grain structure and it gets wimpy but you have to over shoot it always. Which is probably why the people with torch and socket report decent results, it sort of levels off so to speak.