Gas Blowback is a mechanism commonly used in airsoft and some firearm replicas that simulates the recoil of a real gun. It operates by using compressed gas, typically green gas or CO2, to propel a BB and cycle the action of the gun. When the trigger is pulled, gas is released, pushing the BB out of the barrel while simultaneously cycling the slide or bolt, creating a realistic shooting experience. This system allows for a more authentic feel during gameplay, as the blowback action mimics the movement of a real firearm. However, it requires regular maintenance and can be affected by temperature changes, which may impact performance.