I recently purchased the Hornady Case prep center. I am having difficulty with installing the case lock plunger. There seems to be a small metal stud limiting access for installation. It really seems like this should be a non-issue from videos I have watched but I just can't seem to determine any way the plunger will fit even if the shell holder is not placed on it. Anyone else using this Prep Center have a solution? I am about to call Hornady but they are not available on Fridays and will have to wait until Monday now.