A gunsmith friend in Dalton, Ga made up custom based on a 264 Win mag A.I. He blew the shoulders out with a 40* shoulder. He had a wild following shootng the 120g Sierra Match kings at 3550+ with 26" barrels, he liked the #5 best with a #4 at a minimum.
He said that he had recorded over 65 one shot kills on deer at some pretty respectable distances.
Winchester brass is tougher than Remington and Weatherby brass.