Thank you gents. I will certainly update with pics and a chamber cast once in hand.

If this has the chambering with the step, I will either try a partial pass thru 357 dies as you suggest, or wrapping the cases with scotch tape and sizing, like I had to do with my 9.3x72R DR retailed by Weisgerber. That rifle was made before the 1911? standardization of the 9.3x72R and factory brass was too large.

Now the waiting begins.

Chris