On my list of stuff to try is a .457 RB in a .458/.50 sabot for just such work. The sabot should eliminate any tendency to “strip”. .457 is the correct size for the Ruger Old Army, BTW. Gets shaved to fit the cylinder when seated and then fired through the .451/.452 bore.
Light charges should keep damage to a minimum. Have the sabots on hand already, just need to remember to take them when I take my Knight to the range for its annual checkup.
