HalH I would go faster for the 257 Wby. If I re-barrel I want to shoot the 128 Hammer and they recommend a 1-7" twist. I think a 1-7.5 might work but would have to check the numbers. It would shoot all bullets but the lighter weight varmint and target bullets which are too frangible for the Weatherby anyway.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli