I had it happen to me also, replaced the bottom aluminum part and got a new primer assembly and made sure I did not over tighten the screws, they need to be snug only...
My press had allot of miles on it though, you may have other issues... A quick fix that worked untill I got new parts was using 500 grit sand paper and smooth everthing out as you wait on parts, it will take weeks to get anything from Dillon....