I have a 17AH set from CH4D that has an intermediate die for knocking the case down from .22 cal to .20 cal.
I then use a full length 17 Hornet die (Hornady) to neck down to .17 cal and push the shoulder back.
I trim the cases a bit longer than 1.340 so that on fire forming the neck pulls back to 1.340 (there was some trial and error to get dialed in).
Winchester 22 Hornet brass did not need annealing, but PRVI brass needs annealing post forming, prior to fire forming.
I fire form with a case full (compressed load) of 4198.
Here is a comparison photo of the converted brass and a hand loaded 17 FB
