Dillion had introduced a new add on for the 550 and I think soon the 650 presses.
These is a new pin for the linkage. It has a grease zert on the end so you can grease your linkage much easier now. The also redesigned the linkage pin to incorporate a spiral flute design to distribute the grease evenly.
When I talked to the Dillon guys they said it wasn't in the catalog yet. But, if you called them and asked for it they would sell it to you for aprox. $40 +Shipping.