The only manual that I found loads for the .375 Magnum Improved (Ackley) is in the Ackley manual. In that book Ackley states "There are several versions of this cartridge like the .375 Weatherby which are equally as good as the Ackley version."
In that book the loads for both the .375 Magnum Improved (Ackely) and the .375 Weatherby are ostensibly the same.
I have had a custom .375 Ackley Improved for many years made up for me by the late Floyd Butler and I have worked up loads on my own using both the data and my observations.
There must be data online.
