I built a 257 AI on a Czech mauser a few years ago and LOVE it. I have a quarterbore Roy and love that too, but the Better Bob is SO much more "shootable".
This pronghorn that I killed with a 200 yard offhand shot resulting in a DRT seemed to have been impressed:
I wouldn't even start such a build today; I would pick up a 84 Classic and call it better than good!