There's a couple of .41 Colt molds in the fun box, the old Ideal .386 diameter hollow base and a .388 diameter SWC. So was thinking about those undersized chambers on the Pietta and a push through sizer.
The undersized chambers need to be reamed out one way or the other. And a push through sizer could be used to reduced the .41 boolits.
So if the groove diameter is .375 then .377 would work for the reamed diameter on the chambers. The boolits would need to shear off on the chambers mouths so a push through sizer something around .383 would work. And the rear ends on the boolits would get sized down in the Lyman 450 press to slip into the chambers, about .375 diameter.
This is looking workable and some old molds could be called into service for the .36.