How does a percussion lock operate?

A percussion lock operates by utilizing a hammer that strikes a percussion cap, which is a small metal cup containing a sensitive explosive compound. When the hammer hits the cap, it causes the compound to ignite. This ignition creates a flame that travels through a small hole in the gun's barrel, igniting the main powder charge within the barrel. This mechanism was a significant advancement over earlier ignition systems, providing more reliability and faster ignition.

The other methods presented in the options do not describe the operation of a percussion lock. For example, using a spark from flint refers to the flintlock system, which predates the percussion lock and relies on striking flint against steel. A vacuum mechanism is not a method used in firearm ignition and would not be practical for this purpose. Lastly, using a match to ignite powder is characteristic of earlier matchlock systems, which were less efficient and reliable compared to the percussion system.