In decades gone by, RCBS shellholders had a center hole diameter of about 0.313", as opposed to the current 0.262". This might be going back to the days of the A2 press.
I have such a press with what might be the early primer arm assembly. Said assembly has a sleeve diameter of 0.282", which obviously won't fit through the modern shellholders. I prefer priming on this press, but only have the one shellholder.
Any chance readers here have the older shellholders (with the 0.313" centerhole) for .30-30 and .30-40 Krag? If you do, I'd be willing to swap for modern holders, or purchase out right. Other, older shellholder brands possibly had the larger center hole as well. I'm not particular as to brand, but this is a standard base that's fully compatible with modern holders.
Thanks
PBSmith