What do seconds in a duel do? How common?

I’m aware of the fouling problem, but my experience is mostly with rifles. As far as accuracy goes, I once got an eight inch group with a repro brown Bess after a little tinkering with the charge weight, and I’m nobody’s idea of an expert.

The smoothbore pistols surprised me, because it’s sort of counterintuitive.

If you want accurate, get “The Duelist” (Ridley Scott).