Eric,
You don't need "cast bullet" data for cast bullets. For any revolver cartridge, including the Magnums, there is no issue in using jacketed bullet data with cast bullets of reasonable hardness, ca. 12-15 Brinnell. If you study older data from reliable sources, the powder manufacturer, you will often see that their cast bullet data is equal to, sometimes slightly higher, than their jacketed bullet data!
In this case Hodgdon lists a Long Shot load for .38 Spl. +P for the Hornady 158 gr. XTP at 5.5 grains L.S. Listed pressure is 17,000 PSI, NOT 17,000 CUP! Regardless what they call it this is SAAMI MAP for standard pressure .38 Special. Velocity shown is 965 FPS from a 7.7" barrel. Vented is not specified.
Unique, CFE-P, and WSF may be a bit more efficient, but Long Shot definitely seems to have a place in the equation, all "Humble opinions" notwithstanding. If you aren't going to be just a bit adventurous you have missed a large portion of the fun of reloading!
