Brett wrote a book on gun powder in which he discusses the gun powder manufactured in this period. IIRC, he describes how the powder made then was better than what we get today. He makes it himself as well.we don't have any manufacturer today making a Civil War "spec" powder so saying 60g of period 2f is more energetic than modern charge of Swiss 45g 3f really can't be proven.
Thank you for the very informative post, Dave951. We don't have anything like the N-SSA out here. We have BP matches, but almost everything is flintlock/fur trade related.