For the last few months I have been having issues with the primer slide sticking and not always picking up primers (loading large pisto 2-300 rounds per week). I cleaned the slide and machine frame with alcohol and polished the area with steel wool. Still I would have problems after 40-50 rounds. Side not picking up primers, sticking, etc.

Yesterday I visited Dillon's show room to pick up a few items and I happen to look at the 550 they had set up in the display area. Under the primer side there is a small steel plate that runs from the back of the machine frame up to just before the ram. When I asked the helpful young lady she indicated that the presses contained this part for last 5-6 years. My press is about 12 years old and did not have the steel plate. This plate is held in place by the two screws that secure the auto primer feed to the body of the press. I is positioned between the bottom of the primer slide and the machine frame.

I installed the metal shim when I returned to my loading room and ran about 200 rounds, no more primer hick-ups.

FYI if you don't have this metal shim between the primer slide and the machine frame you might want to contact Dillon

TB