An agricultural baler comprising: a frame; a baling chamber mounted to said frame and extending generally fore-and-aft with respect to an intended direction of movement of the baler; a plunger mounted for reciprocation within the baling chamber for compressing crop material fed into the baling chamber to form a bale thereof; a stuffer chute assembly comprising a curved upper wall and a curved lower wall forming a stuffer chamber, the stuffer chute assembly comprising a feeding mechanism with a plurality of tines for moving crop materials through the stuffer chamber and into the baling chamber, the stuffer chamber communicating at one end with a crop receiving inlet opening through which crop material travels from a pickup assembly into the stuffer chamber during operation of the baler and an outlet opening defined by an opening into the baling chamber; wherein the upper wall has a rear portion that extends downwardly and forwardly from the baling chamber and a forward portion that extends generally above the inlet opening to the stuffer chamber, with the rear portion having a higher elevation than a middle portion of the upper wall, and wherein the upper wall comprises a plurality of laterally spaced apart wrappers (52,56) with adjacent wrappers (52,56) forming slots (70,72) extending generally from said crop receiving inlet opening to said outlet opening for cooperation with said tines of the feeding mechanism, wherein the wrappers are movable relative to the lower wall at a forward end and at a rearward end of the upper wall so as to change a cross-sectional dimension of the stuffer chamber; a rear wall adjusting mechanism for setting a rear end of the upper wall in a predetermined position. characterised in that the forward portion of the upper wall has a higher elevation than the middle portion of the upper wall; and in that the baler further comprises a forward wall adjusting mechanism for setting a forward end of the upper wall in a predetermined position. a frame; a baling chamber mounted to said frame and extending generally fore-and-aft with respect to an intended direction of movement of the baler; a plunger mounted for reciprocation within the baling chamber for compressing crop material fed into the baling chamber to form a bale thereof; a stuffer chute assembly comprising a curved upper wall and a curved lower wall forming a stuffer chamber, the stuffer chute assembly comprising a feeding mechanism with a plurality of tines for moving crop materials through the stuffer chamber and into the baling chamber, the stuffer chamber communicating at one end with a crop receiving inlet opening through which crop material travels from a pickup assembly into the stuffer chamber during operation of the baler and an outlet opening defined by an opening into the baling chamber; wherein the upper wall has a rear portion that extends downwardly and forwardly from the baling chamber and a forward portion that extends generally above the inlet opening to the stuffer chamber, with the rear portion having a higher elevation than a middle portion of the upper wall, and wherein the upper wall comprises a plurality of laterally spaced apart wrappers (52,56) with adjacent wrappers (52,56) forming slots (70,72) extending generally from said crop receiving inlet opening to said outlet opening for cooperation with said tines of the feeding mechanism, wherein the wrappers are movable relative to the lower wall at a forward end and at a rearward end of the upper wall so as to change a cross-sectional dimension of the stuffer chamber; a rear wall adjusting mechanism for setting a rear end of the upper wall in a predetermined position. characterised in that the forward portion of the upper wall has a higher elevation than the middle portion of the upper wall; and in that the baler further comprises a forward wall adjusting mechanism for setting a forward end of the upper wall in a predetermined position.