Michael at 2Blowhards has the story of a Civil War re-enactor. An excerpt:
The guns we re-enactors used are historic replications of Civil War muzzle-loaders. To fire, you tear off -- with your teeth if you're a mensch -- a gunpowder packet half the size of a cigarette and pour it directly down your barrel. You then half-cock the trigger and insert a cap that will spark the gunpowder upon shooting.
The blast of smoke and flame extends 12 to 15 feet. So when the troops get very close, squaring off against each other -- as we did -- they are instructed by their captains to shoot up to keep the show going for the spectators but not take anyone’s face off with the flash.
[The definitive - and highly amusing - account of re-enactors is Tony Horwitz's Confederates in the Attic: Dispatches from the Unfinished Civil War.]