After the firing pin strikes the primer when a rifle fires, what is the subsequent event?

When a rifle fires, the primer plays a crucial role in the ignition sequence. When the firing pin strikes the primer, it causes the primer to explode. This explosion generates a spark that ignites the gunpowder located in the cartridge.

This ignition is the essential step that leads to the firing process. Once the gunpowder ignites, it burns rapidly and converts to gas, creating an immense amount of pressure that propels the bullet down the barrel. Therefore, the ignition of the gunpowder by the primer is foundational, as it sets off the chain reaction that results in the bullet being fired.

Understanding this sequence highlights the importance of the primer in the ammunition's design and function: it is specifically engineered to respond to the firing pin's impact, ensuring a reliable ignition to initiate the firing process.