How does one go about making a Wildcat cartridge?

[Monkeyman]

I want a 6.5x39. It should be a regular 7.62x39 necked down with no other chages such as COL, case taper, primer pocket etc. (unlike 6.5PPC and 6.5 Grendel). This will be an assault rifle cartridge and needs to function with AK mags.

Is it simply a matter of ordering a chamber reamer and set of dies? Any thought appreciated.