"There's also the old idea of cutting an "X" in the end of a lead bullet for great tissue destruction.

In any of these cases accuracy would doubtful beyond about two feet."

Not on 12 ga slug. It was my good luck charm. Actually, a cross cut with a thumbnail.

As for steel, I did not know it was used for jackets "back then".

Lead oxide sounds odd to me. Wiki says... "PbO may be prepared by heating lead metal in air at approx. 600 °C."