At present, I know of two Louisiana artillery batteries stationed in northeast Louisiana during the summer of 1863--Benton's and Cameron's. Benton's was at Fort Beauregard, and Cameron's was attached to Isaac Harrison's 15th Cavalry Battalion. I've found indications of unassigned artillery pieces in the area, so it might be possible that Bartlett "borrowed" one. He might have assigned cavalrymen to handle it, or artillerymen not assigned to a specific battery might have had charge of the piece.