I saw at stevespages.com for the 450 ackley they show
81.0 to 90.0 grs of IMR-3031 with a 500gr bullet. They
dont show 3031 loads for any 500gr bullet for the 458 lott.
How can they use 3031 in the ackley and not in the
lott? They are both based on the .375 H&H case.I used 3031
and hornady 500gr sp in my 458 african rifle and got great
velocity with it.

As I understand it, Stevespages.com is a hobby site and not intended to be complete. But you could submit your 3031 load to steve for him to put on his site.

Saeed has this info on the reloading pages http://www.accuratereloading.com/458lott.html