Yep, that is the Gil Sengel article I mentioned earlier.
No teeth gnashed over that, just found it to be the usual gossip about the SAAMI .458 WM,
and some nuggets of truth of the superiority of the SAAMI .458 WinMag.
Hard alloy sized to .461" and it will shoot well in the SAAMI .458 WinMag with 1:14" twist.
Sure, if you want to get "Special" about it, use a 1:20" twist with a SAAMI chamber,
for a rifle dedicated to cast bullets.