How about .475 Gungnir, the name Odin's spear?
Personally I never liked the looks of severely rebated rims, even if people say they function well. The .284 Winchester looks good with the rim only 0.028" smaller than the head, and the .450 Bushmaster based on it seems to work well enough. The .458 SOCOM with it's rim rebated 0.068" apparently works too, but there must be a limit where it's just too much of a difference in diameter. Or is it just a case of me judging a book by its cover?