I have had very good accuracy using a Lee 250 grain RFN bullet, with 6 grain of Red Dot. The bullet casts easily, and I find it is long enough to provide good accuracy. The load is relatively mild, but clearly a .45 slug weighing 250 grains at 700 fps is going to recoil more than a .38 cal 148 grain WC, at the same velocity. I have not had the same accuracy results with the shorter 200 grain bullets.
Sometimes the 200 grain SWC, designed for .45 ACP will provide good accuracy, with about the same powder charge. Naturally the 200 gr SWC will cut much sharper holes for marking.