I needed to order another hand tool for primer seating as my old RCBS is now missing, thanks to my dog, the large primer stem and cup. Bought another new RCBS which is a different design but it still utilizes standard RCBS shell holders. Found it frustrating changing shell holders as it requires removing and then replacing a linkage system that isn't easy. Decided to purchase a Frankford Arsenal model as I was told it a can also use standard RCBS shell holders--guess what, it can't. It came with twelve of their shell holders but not in one I needed, for 38-40 and 44-40. Found out Frankford Arsenal doesn't even make one for that caliber. Luckily I discovered(I hope) that Lee shell holders for their hand held tool will fit the Frankford Arsenal. I have ordered the Lee shell holders and am awaiting their delivery.
I find all this annoying. I don't see why these things can't all be made using standard shell holders. Not the first time I've run into this.