Airsoft Spring guns works just like an ordinary spring airgun. As you "cock" your gun, a piston head within a cylinder moves rearward to draw air into the cylinder and compresses the spring behind the piston. At the end of the piston head’s travel, a hook or "sear" engages the piston and holds it in place with the spring at full compression. When the trigger is pulled, the sear releases the piston, allowing it to travel forward from the energy released by the compressed spring. The air pressure generated inside the cylinder creates a jet of air that propels the BB and sends it on it’s way through the barrel and outward to the target. A simple process as this, earns the simple designation of "Air" or "Spring" gun classification in AirSoft. Semi Automatic and Full Automatic is not possible with spring guns