After reading an article in the Varmints Hunter magazine about the .257 Weatherby, I called the author and talked with him a while.
He has shot the .257 Wthby for 30 plus years. He shoot cull deer on some of the ranches in his area and has killed over 350 whitetail.
He stated he had more "dead right there" shooting the 85,87 & 90 grain bullet than the heaver 100 and 115, & 117 gr bullets.
He said all bullets killed the deer but deer shot with the heaver bullets tended to run 15 - 20 yds before dying and the deer shot with the lighter bullets died in their tracks. As with any bullet good shot placement is still required.

Hal