[tpg]

I don't think there's actually an inconsistency. On page 8 of the book linked, it describes "the charge, consisting of powder and duck-shot ...". Merriam-Webster[1] defines "duck shot" as "a medium-heavy lead shot used in duck hunting". Muskets used smooth (unrifled) barrels until around the middle of the 19th century [2], so they would have been well suited for firing shot shells.

[1] http://www.merriam-webster.com/dictionary/duck%20shot

[2] https://en.wikipedia.org/wiki/Rifled_musket#History_and_deve...