What component of percussion cap firearms was a significant innovation?

The notable innovation in percussion cap firearms was the explosion of a small metal cap. This development marked a significant improvement over previous ignition systems, such as flintlock mechanisms. The percussion cap system utilized a small, cup-shaped metal cap filled with a sensitive explosive material. When struck by the hammer of the firearm, the cap would ignite and produce a flash that ignited the main charge of gunpowder in the barrel, allowing for a more reliable and quicker ignition.

This change meant that shooters no longer had to rely on the complications of a burning wick or the wear and tear associated with striking flint against steel, which often resulted in unreliable ignition due to misfires caused by damp conditions or worn components. Moreover, the addition of a spring mechanism provided improved consistency in striking the cap, but it was the cap itself that represented a breakthrough by allowing firearms to be fired in a variety of conditions with greater reliability and speed.