This musket, and variants, were used by the British Army from the early 1700s until the 1800s. Please note, the cartridge would have contained the musket ball. It was not put in separately. To load and fire the flintlock musket the soldier had to carry out a set sequence of movements. First, he bit one end off a paper cartridge containing powder and musket-ball. He dribbled a small amount of powder into the priming pan, and clicked the steel (a metal plate which the flint would strike) back to cover it.
Quite difficult if crouched behind a rock for cover. Beware of the hang fire.