To make 22Jet brass I use 4 dies: 8mm,7mm,6mm, & 5.56. I made the form dies by cutting off LEE RGB dies ($14/set) in 8x57, 7mmMag, 243, and 22-250. Then it is like neck sizing the .357 brass 4 times. Easy. (Anybody need LEE bullet seating dies?) I may get another 7mm die (7-08 will probably do it), this one is as far down as it goes. I finish with a 22Jet die.
Once the cases fit into the chamber they are ready to fireform.
Jet brass from .357.
75 rounds of many kinds of range brass. cleaned and annealed.All processed from .357 to .22 Jet in less than an hour. No failures.