A round baler is disclosed having a bale forming chamber. A duck bill assembly (28), which comprises a pair of elongate plates (22) that are biased towards one another to grip the wrapping material (30) between them, is movable between an advanced position and a retracted position to introduce the free end (31) of a wrapping material (30) drawn from a supply roll (16) into the bale forming chamber of the baler. A cutting device is located between the retracted position of the duck bill assembly (28) and the bale forming position for severing the length of wrapping material (30) wrapped around the bale (10,110) in the bale forming chamber at the end of a bale wrapping cycle from the supply roll (16). In the invention, a clamping device is provided to apply an additional force to the duck bill assembly (28) while the duck bill assembly (28) is in the retracted position in order for the wrapping material (30) to be gripped more firmly by the duck bill assembly (28) between bale wrapping cycles.
