G'day Anthony,
I read an article on Accurate Shooter .com and emailed a bloke @ Hornady. He requested either 2 fired cases or a chamber illustration. I sent him cases and he returned the die after about 6 weeks.
If you go down the Hornady path and you already have fire formed cases then send them.
If you're doing a rifle build I reckon your gunsmith could run your chamber reamer into a blank body die. He could I'm sure, also drill the hole and possibly make the plunger. Doesn't really look all that difficult.
As usual, I made a few mistakes forming these cases early ,eg I bent the plunger by hitting too hard with a steel hammer instead of just firmly with a rubber one. I've also learned to set the die to the point where the cases come out a "fraction" to long. I then full length resize ensuring that head spacing is perfect.
Maybe I can take a few pics if readers are interested!
Regards,
Belly
Michael Bell