I have found for good primer feeding the tray needs to have at least 150 primers. Never let the primer trough get low or it will feed very poor or not at all. The priming system on the Pro1000 is the Achilles heel of this unit. I often times just run brass that I hand primed when I need to get through fast.Lol.. now that a powder measures correctly ( diffrent powder) now my primers won’t feed.. what is wrong with me.. lol