Does anybody happen to know the factory Barrel twist for a Winchester model 70 XTR featherweight in 257 Roberts?

You would have to put a tight patch on a jag and check it. Ideally it should be 1-10 but Winchester did do some in very painful 1-14 barrels for a while. What was going through their heads, no one knows. I suspect if you blew into the engineers right ear, leaves, grass and twigs would probably fly out the left. The 75 grain Sierra HPs shot OK but the big, long 117s would often keyhole.