When gun is fired why does it recoil?

When a gun is fired, the rapid expansion of gases from the burning gunpowder creates a high-pressure force that pushes the bullet forward out of the barrel. According to Newton's third law of motion, for every action, there is an equal and opposite reaction; as the bullet is propelled forward, the gun experiences an equal force pushing it backward, resulting in recoil. This backward movement is often felt by the shooter as a jolt or kick.