I too have loaded, 38 long with heeled base bullets for this in the Avenging Angle configuration.
The 51 barrel I had lined to .357.
I used heeled Bullet's I had gotten from GAD, I won't recommend him though

They had to be sized, and in some cases the casting was so bad I just remelted them

Nevertheless, the ones I sized and loaded with BP shoot well enough @ CAS distance.
In the 7.5 length also BP but I use both a 148-gr semi wad cutter and Round Nose bullet.