Abstract: A gas powered gun for firing paintballs dispensed from a magazine includes a bolt slidable within a breech section, a slidable hammer connected to the bolt and a spring to bias the hammer towards a forward firing position. A trigger operates an electrical circuit that includes a solenoid adapted to move a sear mechanism so as to release the hammer when the trigger is pulled. The solenoid has an actuating member movable from a lower position corresponding to the cocked position to a raised firing position at which the sear mechanism is disengaged from the hammer. An annular sealing member mounted at the bolt's front end is engageable with the barrel. The preferred sear member is elongate and pivots about a central transverse pivot axis. This sear member is engaged at its front end by the actuating member in order to release the hammer.