Here's another interesting bit of dialog on shot:

https://books.google.com/books?id=9BNZAA...hot&f=false

What is interesting is in this case 'plumbago' as ref.'d is speaking of plain black lead being used as a 'polishing agent' for the round shot. However, what is most generally referred to as 'plumbago' in older sporting literature is speaking to the misshapen or deformed shot and sometimes to shot that has been purposely flattened.