HC the resizing die is going to neck down the 7.62 and straighten out the taper to a close to 6mm PPC it is a step before the Full length resizing with a standard 6mm PPC die. IT is not going to straighten out the case to the end It is going the wrong way as far as trying to get to a 9mm neck. ths would only be usefull if you were trying to make the 7.62 into a 6mm PPC
That is a great price on the 6mm brass not sure why it will not fit a PPC bench rest chamber. this has really got me thinking of doing a 6mm PPC varmit build.I am going to see what the deal with why it wont fit. likly it is not necked to final size or final sized but really good price the same. high quality PPC brass is close to a $1.00 a round.
I would start with that 6mm PPC brass and expand the neck to 9mm with a taperd expander. this is basicaly a taperd rod that gradually opens up the mouth you would then use your FL die to get it to the proper sizing you may have to aneal the cses first. DO YOU HAVE A DIE ALREADY MADE FOR THIS?? Fire forming is not that tough and there are guys that fire form right in the dies with the decaping pin removed, with a set up that uses a spring loaded pin that screws right onto the die itsself. there is a good description in my making cartridge conversion book. you dont need to fire a bullet down the barrel many use a light powder charge and some cream of weat to build up the pressure. IF you dont have a die made up yet I would consider a 308 win case cut down to 1.5" and then necked to 9mm. this would be more like a 9mm benchrest round or like a 308x1.5 barnes that i have mentioned before but opend up to 9MM it would have even more capacity than the PPC round.
you can by a lot of primers and powder for what the forming die costs + if you fire form you can simply use the AK brass. I have been lurking in on some of the reloding sites and bench rest sights and there is a lot of wildcating info there.