Thanks to all who replied to my post on .17/.357. I had a chance to visit my departed friend's house today to look for dies and load data for the rifle he left me. Its a .17 based on .357 mag pistol brass.

Sadly, he was not very organized. I found no load data. But I did find 2 dies. They were from RCBS, and they were labeled for .17 Mach IV. So that must be what its called.

There was a single forming die (there must be more of 'em somewhere) and a trimming die. So here are some questions:

1) Anyone know what the complete set of dies should include? I'm guessing:
-Several forming dies to neck the .357 case down to .17.
-A neck reamer
-A full-case sizing die?
-The trimming die which I have.
-Any others?

2) Anyone know where I can get load data for this? Is it in the commercial catalogs?

3) Does anyone list the dies in their catalog, so I can purchase any dies I can't find?

the 17 mach IV is a 221 Fireball necked to 17 cal.
Your friend may well have used mach IV dies to make his 17/357, but I'll bet forming is a several stage process.
I used to make cases for a handgun that was a 357 necked to 22 cal. with a long shoulder. Not the easiest forming job.
T.D.

Thanks for clarifying, T.D. Guess this is going to be as difficult as I origially thought. Shoulders are pretty sharp on these cases I have.

DAVE R:
You may have a 17X357MAX instead of a 17X357mag, if it is then you simply use 17 mark IV load data and dies and a 357mag shell holder, the only difference is the rim on the case, I have a 17 mark IV 12" Contender barrel that I had the rim counter bored into the barrel by a machinest friend so I could use the rimmed case to give better extraction. Albert