Should be no trouble at all to neck down 270wsm brass and trim it back. Lube the neck with caselube and polish off afterward. As far as powder, it is right between the 25-06 and 25 roy capacity wise so start there and be conservative to start with. I'm sure some have their pet loads, but as a wildcat everyone's chamber will vary a bit so you've got to start a full 10% back anyway.Looking for info to get mine going? Have had trouble necking brass down and need load data for 100gr Sierra BT? Any info appreciated...Greg