Howdy Roundsworth,
I have been experimenting with HB 148gr. bullets in an 1851 conversion. I have found that once you get a load with enough pressure to expand the base, they can shoot very well. My very old conversion is a press frame chambered in .38 S&W. I slowly worked up loads. Once I hit the right pressure, the results (accuracy) were dramatic. I can't give you an exact load, but start low and work up, keeping an eye on the data for your cartridge. Obviously, you should never exceed max loads.
Rev. Chase