Old Taffin article includes some necked rounds seating
Information on belling and seating with short necked cases. We know about this with some specific GNR rounds. Gary has good notes on this too.
I actually have a .357 SIG barrel for my G23 and want to play with it. The LEE collet crimper might be a good idea, sure enough. I think I can mod it for other applications too. I bought a 9x25 Dillion barrel cheap for the G20/21, but no dies. I’m thinking the SIG dies, crimper, maybe .356 GNR dies will work for carefully making cases and loading a few.
Kudos for Mr. Taffin tackling such a project and detailing such useful technical info. It transitions to many others.