In time RCBS has had 3 changes to their shell holders, the shell holder on the left was the first design, the one on the right is the second design, the third design has more bevel, the only shell holder that fits the RCBS automatic hand primer is the third design.

I called RCBS years ago and informed them my shell holders would not fit their hand primer, they offered one shell holder with just an address and would exchange all of my shell holders one for one if I would mail them the old shell holders, with 2 lathes and a mill I could modify the shell holders with a bevel before I could get them boxed up and delivered to the post office, I have a few shell holders that do not have the standard .125 deck height and am not willing to give them up.

F. Guffey