Way back, John Buhmiller necked the .378 WTBY mag up to .458.
Roy W. was visiting him in Kalispel in the later 50's at his shop when John was doing some penetration tests with his new wildcat.
After returning to California, Roy brought out the .460 Wtby mag.
This is the story as I leaned from Lester H. Hawkes previously of Kalispel & friends with both Lester Bauska and "old" John.