I know Brian pretty well, and use his Game Getters.
I figure a steel case, flared up at the mouth, to take a suitable bullet, would also give the driver load a bit of support.
Considering that the Game Getter does not support the case at all, and I've never had any issues getting the fired loads out of the case (I use green lods, because that's what I have on hand), the only issue after that, would be to keep the cases aligned with the firing pin.
Cheers
Trev