Southla1. The RCBS book has been out of print for several years now. I keep hoping they'll come out with a newer updated version, but so far I have heard nothing.
I have a copy of the book, so if you need something specific. I can pass it on. My biggest gripe with it is, like the second ed. of the Lyman book, they used all those faster burning powders like Unique and #2400. Those usually don't give the best results. The latest Lyman book has the best data of the two.
Fortunately, I've been casting long enough, that I have all three of the Lyman bullet casting books. I sure wish they'd reprint the first one. Mine has gotten so raggedy from use that it is starting to fall apart. It probably is the most interesting to read, and much of the data was sent in by shooters, who also recorded their comments on the loads. It is also surprising to see how many people used cast bullets for serious hunting, up to and including moose, some with the 30-30 yet.
If you find a copy in decent shape,get it. It's worth the price just for the reading.