As the barrel returns forward to its initial position the bolt remains behind and thus the spent shell is ejected through a port on the right-hand side of the receiver. Then the bolt returns forward and feeds another shell from the magazine into the action.
When the barrel moves back to its initial position, the bolt remains stationary, causing the spent cartridge to be expelled through an opening on the right side of the receiver. Following this, the bolt retracts and loads a new cartridge from the magazine into the action mechanism.