It can be done. The current BAT machine combination PPC/BR boltface is just an opened up PPC setup. It always seems that the PPC ejection suffers with this combo face in my experience.I am going to use the rifle for Benchrest so a 6PPC would certainly be ok.
I had planned to have a 6BR that was shortened 0.100" to have the same case capacity as a PPC but a greater diameter to length ratio.
Since it is already an excellent cartridge for Benchrest I will probably just run it the way it is.
I am still interested to know if it can be modded to BR/PPC combo in case I want to change down the road.