A round baler is provided with a bale-forming chamber and boundary apparatus of the bale-forming chamber that can be moved into an open position for ejecting a completed bale. The axial dimensions of the bale-forming chamber can be changed by at least one side wall that can be moved by means of an adjustment drive. The adjustment drive is configured such that the axial dimensions of the bale-forming chamber are initially increased during the ejection of the bale relative to the dimensions provided for generating the bale and then reduced again for braking the bale.
