A pneumatic animal stunner comprising: a housing having a catch piston chamber, a stunning rod chamber and a front end forward of the stunning rod chamber, a supply passageway in the housing between a source of pressurized fluid and the catch piston chamber; a stunning rod slideable within the stunning rod chamber capable of being driven forward along a longitudinal axis towards and out of the front end of the housing; a catch mounted within the housing for alternately holding and releasing the stunning rod; a catch piston disposed adjacent the catch and in sliding contact within the catch piston chamber, the catch piston being adapted to move between a first position urging the catch to hold and prevent the stunning rod from being driven forward, and a second position permitting the catch to release and permit the stunning rod to be driven forward; a first passageway in the catch piston in alignment with the housing supply passageway when the catch piston is in the first position permitting air to flow from the source of pressurized fluid through the first passageway to a rearward end of the stunning rod chamber; and a second passageway in the catch piston in alignment with the supply passageway when the catch piston is in the second position permitting air to flow from the source of pressurized fluid through the second passageway to a forward end of the stunning rod chamber; wherein when the catch piston is in the first position, pressurized fluid may flow from the source through the supply passageway and the first passageway into the rearward end of the stunning rod chamber to drive the stunning rod forward upon release of the catch, and when the catch piston is in the second position after releasing the catch, pressurized fluid may flow from the source through the supply passageway and the second passageway into the forward end of the stunning rod chamber to drive the stunning rod rearward. a housing having a catch piston chamber, a stunning rod chamber and a front end forward of the stunning rod chamber, a supply passageway in the housing between a source of pressurized fluid and the catch piston chamber; a stunning rod slideable within the stunning rod chamber capable of being driven forward along a longitudinal axis towards and out of the front end of the housing; a catch mounted within the housing for alternately holding and releasing the stunning rod; a catch piston disposed adjacent the catch and in sliding contact within the catch piston chamber, the catch piston being adapted to move between a first position urging the catch to hold and prevent the stunning rod from being driven forward, and a second position permitting the catch to release and permit the stunning rod to be driven forward; a first passageway in the catch piston in alignment with the housing supply passageway when the catch piston is in the first position permitting air to flow from the source of pressurized fluid through the first passageway to a rearward end of the stunning rod chamber; and a second passageway in the catch piston in alignment with the supply passageway when the catch piston is in the second position permitting air to flow from the source of pressurized fluid through the second passageway to a forward end of the stunning rod chamber; wherein when the catch piston is in the first position, pressurized fluid may flow from the source through the supply passageway and the first passageway into the rearward end of the stunning rod chamber to drive the stunning rod forward upon release of the catch, and when the catch piston is in the second position after releasing the catch, pressurized fluid may flow from the source through the supply passageway and the second passageway into the forward end of the stunning rod chamber to drive the stunning rod rearward.