Indy,
You might want to check Alliant's latest data, instead of relying on 7-year-old stuff. My experience with Alliant over that period is they often didn't try every powder in a certain load combination, resulting in a lack of overall perspective on cartridge potential.
The highest velocity with 180 Speer Hot-Cors in their latest goes like this
.300 H&H--2996 (26" barrel)
.300 Win.--3089 (24" barrel)
.300 Wby.--3147 (24" barrel)
