This is a sample file for the Lee Pro1000 Case Separator Collator Insert (https://www.thingiverse.com/thing:3380330). Use this sample to set the parameters according to your setup.
RES = Resolution. This is just the polygon count, to get nicer curves. I wouldn't go over 100.
CDA = Case Diameter Adjustement. The most important variable, it sets the width of the sieve holes. I've found that with my printer setup a 0.5mm CDA is just enough to let the 9mm cases go through and keep the .40 out. Adjust this according to your setup, you might need to insert a negative value.
STN = Sieve ThickNess. This is to set how thick you want the object to be. I'm fine with 2mm, but you might want a sturdier or lighter sieve.