This tray will hold your old traditional reloading dies. Breech lock rings will not sit deeply in the holes. There is no provision for base plates. Strangely though there is a slot for the instruction sheet that comes with each die set. That’s why I think it is designed and intended for beginning reloaders.

I am using these for both Lee dies and Dillon dies. They are great. Small compact and hold even the longest dies. I get them in different colors for different calibers so that at a glance I can tell what the dies are for. ( 38/357 or 40 SW). Each block will hold 5 dies plus the shell holder. Excellent 3D printing job. They are solid and have a smooth finish.