Recoil operation is a mechanism used in firearms that utilizes the energy generated from firing a bullet to cycle the action of the gun. When the gun is fired, the force of the bullet moving forward creates an equal and opposite force that pushes the gun backward, or recoils. This recoil energy is harnessed to eject the spent cartridge, chamber a new round, and reset the firing mechanism. This system is commonly found in semi-automatic and automatic firearms, where the recoil helps to automate the loading process. By using recoil operation, these firearms can fire multiple rounds quickly without the need for manual reloading after each shot.