Bullet weights and powder charges being the same, you will generally get higher velocities with a cast bullet compared to a jacketed bullet. You can push them just as fast as a jacketed bullet. The limiting factor is leading. A lot depends on how smooth your barrel is, bullet fit, lube used, bullet hardness, etc. Best to start off low, say 1200 fps., then increase until you start to see leading. A bullet with a gas check may help if leading is a problem. Unless you really need max. velocities, I would work on finding an accurate mid-range load that did not lead, say a 240 grain in the 1200 - 1300 fps range.
Larry