What happens when the powder in a cartridge ignites?

When the powder in a cartridge ignites, it generates expanding gases, which is the fundamental principle behind how ammunition operates. This rapid combustion of gunpowder creates a significant increase in pressure within the cartridge case. As the gases expand, they push the bullet down the barrel of the firearm at high speed, enabling it to exit the muzzle and travel toward the target.

The creation of expanding gases is essential for the firearm's operation because it is this pressure that propels the bullet forward. Without this reaction, the bullet would not be able to achieve the necessary velocity for effective and accurate shooting. The process is a critical component of how firearms function and is central to understanding the basic mechanics of shooting.