Gone.

Nice mod.

Just wish you had some arrows in the pic to show the "black" part you are describing.

I am not familiar with the RCBS progressive, so maybe it was me.

This mod will help out people with this press.

The "black thing" is the cam follower or "shoe" at the extreme right side of the photo.  His bracket locks out the cam driven stem to the left, so it does not cycle left and right when the ram moves up and down.  I suppose  one could pull out the primer carrier strip (yellow thing running horizontal in the background).  But, there may be intermittent times when one wants to cycle the press and not have a primer cycled into the primer insert station.

I can see where this would be very helpful during setup and timing, and a nice safety feature also.  I would hang a big red tag on the "lock-out" device to remind myself that the primer insertion step is defeated.  Dumping powder into a case and inserting bullet into a case with no primer could be problematic.

Gone

Gone