Same for cast. The velocities are so low in the .458 SOCOM that you can use the jacketed bullet data without worrying about leading or driving them too fast. It is best to use gas checked bullets though so you do not vaporize the base of the bullets which will increase lead vapor getting into and condensing in the gas block and gas tube. When shooting cast you will eventually clog up the gas tube but considering the thousands of rounds it will take to clog up the tube, a new gas tube is chump change compared to the money you will save using cast bullets. A gas checked bullet just helps prolong the inevitable.
The only problem I have run into is not being able to size the bullets .001-.002 over bore diameter which with cast generally gives the best accuracy. In the .458 SOCOM, .500 Phantom, and .470 Rhino, if you size the bullets over the bore size they will not chamber. Marty cuts the throat tight and right at jacketed bullet diameter so a .459 bullet will not chamber but a .458 chambers fine. Because of that I have not been able to get the kind of accuracy out of cast that I do in rifles that have throats more suitable for cast bullets like the .45-70s, .416 Rigbys, 458 Winny, and most handguns. So far the best groups I have been able to get out of any of them are in the 2.5-4 inch range at 100 yards, 5 shots, depending on caliber and gun type.