I used a 6.5 mm bit to drill the pocket out. I used a drill press on the slowest speed, and checked the depth frequently to ake sure I did not contact the decapping pin. In this case, the decapping pin was able to retract a limited amount, just enough to clear the primer pocket and move around in the case.

In this picture , the shiny bit in the center of the drilled pocket is the tip of the decapping pin, and it has not been contacted by the drill.