ODay450,
I don't think you intended to say what you did: "The Barnes manual only lists data for 1 or 2 powders per bullet." Actually, they list 6 powders for each of the 4 bullets designed for the 458 magnums.
I use the 350 TSX, but they only list that for the Ruger No.1 in 45-70. There's no reason not to use it in a 458 magnum, however.
But I have loaded the 450 X, the predecessor to the 450 TSX.
As mentioned by JPK, Hornady's manual is tops.
