If it is like my old RCBS hand primer, the bevel on the plastic insert that holds the shell holder may not allow the use of other brands of shell holders. I use mainly RCBS dies and shell holders, so there is no problem for me. It is no great financial burden to invest in an RCBS shell holder for each size you use.
Several things to remember. There are two different size plastic inserts and two different size ram rods, one set for large primers and one set for small primers. Make sure you put in the ram rod so the flat surface contacts the primer. The rod is flat on one end and round on the other. It is wise to put a rubber band around the primer tray after you load it with primers.