I have the RCBS round tray, the RCBS square tray, and the Lee triangle trays. I use the Lee triangular trays because they have the fewest problems. I use the Lee trays with the RCBS hand priming tool, not the universal (which I also have). I prefer the shellholder rather than having to compress the spring on the universal going in and then again going out. Using the non-spring shellholder on the non-universal is much smoother.