Re: .257 Wyb. -retumbo-115gr vld starting looad?
Try a start of 66.0 grains, for about 3100 fps, and work up to a max of 69.6 for 3300 fps.
Drop me a line on the Berger site and I'll be happy to forward the complete set of tables for the 257 WBY. Tried to post it here, but the margins wouldn't stay aligned.
Hope this helps,