I have heard of that but both the 470 and 500 are quite a bit smaller at the base so my supposition is that you would need to be very precise with neck sizing to your chamber before fire forming to keep everything concentric. And that you would probably want too keep pressures low which the No.2 is I guess.

I have a bunch of 577/500 basic brass which can be used for the No.2 or the 3-1/8" as well as a set of forming dies. I have just started to try this and could certainly try a couple pieces of 470 to see how close it comes out.

Anybody know what to trim the basic cases to before reforming? I am finding that trimming to the correct pre-forming length would be much easier as the cases are cylindrical rather than trimming the tapered formed cases. I guess I will make up a system on the lathe to trim formed cases if I can't nail down a pre-form length.