Sir Matt, Save the H4198, best for 250-350-grainers. CFE-223 is excellent with 500-grainers. Should be about perfect for the excellent 450-gr TSX too. Will review my data after domestic chores are done.
I don't have any load data for CFE223 in the 458 Win mag, but I have a lot of it
I got banned on another web site for a debate that happened on this site. That's a first