You can also oven heat treat your plain cast wheel weight bullets and get an almost exact desired BHN using the temperatures and time in this article. http://www.lasc.us/heattreat.htm The trick to success is controlling and knowing exactly what the temperature of the oven is.
I have used straight wheel weights for 38-55 and other non gas checked. I was quite happy with thre results--especially with a Lee die and the 38-55. I would to try something different with gas checked 338 and 30-06. I will start with the water quenched and move into alloys. I have also ordered a RanchDog 308 size mould.