Out in the open it's scary enough when you are burning off a train of old stuff: it's GONE before you can even get out of the way. Bullseye, for example, is extremely slow in comparison.
Inside a cartridge, I don't even wanta guess.
I have no idea how they do it in the movies. There, they always show a sputtering trail of Black leading to the powder-barrels in the pirate ship or something. In real life, it would be "FFFFfft!BOOM!!!" and the Hero would be looking for a parachute among all those pirate-ship parts surrounding him.
Not even close to true. Mythbusters did an episode on exactly this subject and they found they could easily outrun a trail of burning black powder. Go to 4:40 to see the first run.
[youtube]b-IRI1bA5jw[/youtube]



















































