Dillon 1100 with Mark 7 Auto-drive. Reloading 9mm major with AA7 10.5, so case is almost full. When the shellplate is full, after the powder is dropped, there is a severe clunk/jerk in the shell plate and the powder in the case goes flying everywhere leaving the case almost half full. My actions: I removed shell plate, and the indexing pawl, cleaned under the plate and top of the surface where the plate rides. Ball bearing has the perfect bounce. Cleaned the indexing pawl and reinstalled paying close attention to shell plate tightness. Resumed reloading and for the first 10 rounds or so no issues. All of a sudden the jerk again. What else could it be?