The reason you've had no responses is the 375 Ruger is a bottleneck rifle cartridge 3.34" long, same length as .30-06. The Alaskan is a short barrel Redhawk revolver and its cylinder would be far too short for that round to fit into.
The Alaskan is available in .480 Ruger, which uses a 0.475" bullet. Is that perhaps what you were asking about?