Canadian Firearms Safety Course (CFSC) Practice Exam

The component of a rifle cartridge that fires the powder charge is the primer. The primer is a small, crucial part located at the base of the cartridge. When the firing pin strikes the primer, it ignites the primer's sensitive material, which in turn creates a small flame. This flame is what ignites the powder charge within the cartridge casing, causing the gunpowder to combust and generate the gas pressure needed to propel the bullet down the barrel.

Understanding the function of the primer is essential for grasping the mechanics of how ammunition works. It is sometimes overlooked, yet it plays a vital role in the ignition process. The bullet is the projectile that exits the barrel, while the casing holds all the components together and the rim can be involved in extraction and ejection but does not ignite the charge. Thus, the primer is the key element responsible for initiating the firing sequence.