On the bolt’s return, a new shell is picked up and guided into the chamber. The bolt then moves forward under power from an additional spring that is in the stock. There is also an ejector built on the rear of the barrel that kicks the spent shell out. The barrel then returns, using the stored energy of the recoil spring. Once they have reached the rear of the receiver, the barrel and bolt unlock. The force of the recoil moves them both backwards and compresses a spring that is coiled around the magazine tube. Here is a simple description of how this type of action works: when a round is fired, the bolt and the barrel are locked together.