I REALLY wish, just once in my life, I could say, "Budget is not a problem". Just once...
Well, most of those making custom case are turning them on a machine lathe, you could too, although, I imagine that setup is a biatch.
Commercially, they are punched and drawn from sheet brass. I toyed with that idea years ago, but really could not justify the time to build the machinery and each punch, drawing die, press, forming dies, etc.
I would have to have something that would do 5 at a time in a single stage deal, 20ton pneumatic hydraulic press.
Punch out 50 disks. Set up next stage of drawing case length, do all 50.
Set up to punch for flash hole and primer pocket. Do all 50
Set up for uniforming case web and Swaging extractor groove. Do all 50.
Set up to develop body taper and neck. Do all 50.
Set up to trim to length. Do all 50.
If I went this far, I might as well uniform the case mouth on all 50.
Anneal brass do eliminate work hardening. Do all 50.
VERY TIME CONSUMING if you are doing an easily obtainable case. Something extremely exotic, maybe. But it will NEVER pay for itself and will only be of value if you have a brass supply and are looking for some sort of self-sufficiency. I am not there yet, so I will continue to buy/ pick up brass. But you, you knock yourself out and, PLEASE, let us know how you make out.
ETA: Sorry, re-read the post. When I was thinking this it was for rifle, hence my forming case taper, neck and shoulder step. Not needed in the pistol rounds...my bad.
Ted