When the pressure in a cartridge exceeds the friction holding the bullet, what happens next?

When the pressure inside a cartridge increases to a level that exceeds the friction holding the bullet in place, the bullet begins to leave the cartridge. This process is a fundamental aspect of how a firearm operates.

As the primer is struck by the firing pin, it ignites the gunpowder inside the cartridge. This rapid combustion generates a significant amount of gas and pressure. Initially, the friction between the bullet and the cartridge case keeps the bullet secured. However, once the pressure surpasses the threshold of that friction, the bullet is driven forward out of the cartridge and into the barrel of the firearm. This forward movement is what propels the bullet out of the firearm when it is fired, leading to projectile motion towards the intended target.

The other options do not accurately describe what happens when the pressure in the cartridge exceeds the friction holding the bullet. The bullet does not remain in place, nor does the case explode in these circumstances; rather, it is the intended and expected outcome of firing the weapon. The primer is responsible for initiating the combustion, but it does not detonate after the bullet starts moving.