|When we lived in Iowa I occasionally shot a black powder pistol. I thought it would be interesting to see what kind of flash it made at night. I loaded the pistol with powder, no ball (shooting live ammo at night seemed like a bad idea), put the camara on a tripod, locked the shutter open, and let fly. Based on my distance from the small tree that's occluding the flash on the left, I estimate the blast traveled about 6 feet. I'm not sure if having a ball loaded would have changed the form of the muzzle blast.