Why does someone get pushed backward when they fire a gun?

When a gun is fired, the bullet is propelled forward due to the rapid expansion of gases produced by the burning gunpowder. This action generates an equal and opposite reaction, known as recoil, which pushes the gun—and the shooter—backward. The amount of recoil depends on factors like the gun's caliber and weight, as well as the shooter's stance and grip. Essentially, the shooter experiences a backward force as a direct consequence of the bullet's forward motion.