Anschutz (and others) moment
basically when a gun is otherwise behaving really well until a shot goes way outside the KZ and you see it clear as a bell with no movement or twitch of the reticule even at 25yds or so. Ignoring that one the next shots are fine again.
Is this a build up of something unpleasant in the bore? The shot coughs it out but the pellet goes where you didn't aim and there isn't so much as a spider's web between you and the faceplate?
I suspect a rigorous procedure of barrel cleaning (light or thorough?), "re-lead" with N shots may be the answer?
I am not asking for the secrets of the top AAs but I am curious as to what other explanations may be out there (other than nodding off "at the wheel" ).