Since the main propellant cost can be found deep inside the gun barrel and therefore impractical for being specifically lighted from the surface, an intermediate is needed to relay the ignition. While in the earliest black powder muzzleloaders, a fuse was used to immediate a small flame through a touch https://messiahlbsiy.rimmablog.com/16010443/rumored-buzz-on-cci-percussion-caps-11-box-of-1000-10-cans-of-100