I know that a lot of people download to 45 70 levels in the 458win in order to get practical use out of the rifle when not after DG. Is it feasible to do the same in a larger case like the 450 rigby or dakota, or would the loads be too inefficient to be worthwhile?
boet

I came across some loads in a few manuals that used AA5744 powder for reduced loads in the .458 win mag. I contacted Alliant's tech support personel and asked them if I could safley use data for the .458 win mag in my .458 lott. He told me that I could safley use the .458 win mag data but I would have to increase my charge a grain or so if I wanted to equal the published velocities. I have stuck to the published data without increasing the charge.

Thanks. I will apply the same rule to the rigby and see how it works out.
boet