When a rifle fires, what happens immediately after the firing pin strikes the primer?

When the firing pin strikes the primer, it creates a small but powerful explosion that ignites the gunpowder in the cartridge. This chemical reaction generates a rapid build-up of gases which then propels the bullet down the barrel and out of the firearm. This sequence of events highlights the critical role of the primer in firearms operation, as it serves as the ignition source for the propellant that ultimately fires the bullet.

The other options do not accurately represent the immediate aftermath of the firing pin impact. For instance, the bullet does not exit the barrel until the gunpowder is ignited and the gases build up, which happens after the ignition of the primer. Similarly, the safety mechanism would typically be disengaged before firing; it plays no role in the reaction after the firing pin strikes the primer. Lastly, while the bolt locking into place is essential for the safe operation of the firearm, it occurs prior to firing rather than immediately following the ignition of the primer.