On the fingerlakes of New York State "O" and "OO" gauge fowling guns or Market Guns were used to shoot flocks of ducks at a time as they rested on the water. A man laying low in a boat that was well disguised with brush would loat to with in a few yards of a raft of ducks and were fired. A few ounces of shoot would knock over a hundred or so birds all at once. The birds were then sold at the meat markets in Geneva, Ithaca, Watkins Glen and round about.
I have seen these guns fired during exhibitions, hunting with them has long been illegal. I can imagine them being toted off to a land battle and the carnage that would ensue.