I used a full case of IMR4064 with a paper patched lyman cast 330 gr hp in my guide gun. Kills big bulls in one shot. Load also seemed to work in my guide gun with 405 gr lee cast bullet. At one point, those reloads were cheaper than using 22lr to shoot gophers.
They really brought home the saying, "Never get into a gunfight with a buffalo hunter. Ain't no such thing as cover." Those loads would cut a channel 6" deep and 24" long through clay, hit the gopher behind it, and take half the gopher with it leaving the other half.