Making 458x1.5 brass
.458 WinMag brass is plentiful, and easily obtained. .458 WinMag brass can be used to make .458x1.5 Barnes.
You don't need a dedicated for caliber die set if you can find a 375H&H sizer, and a 45 ACP seating screw that fits in your .458 WinMag seating die.
In this case, the threads on a Redding .45 ACP seating stem fit a Pacific Durochrome .458 Win Mag seating die.