Making cases should be very easy, just use .30-40 or .303Brit cases cut off the the correct length and size with a .44 Mag. die.. the rim will have to be turned down, but that can be done with a drill motor and a file, just put a bullet in the mouth, chuck in a 1/2" drill motor and spin slowly while holding a file on one side and a wooden backup on the other side.
The rim must also be thinned about .005", can just be done on the end and then use pistol primers rather than rifle primers.