A caulking gun barrel system fits into caulking guns designed for pre-filled cartridges. The caddy system utilizes soft-sided recharge packs of fill material ordinarily designed for more expensive caulking machines with built-in barrels. The caddy system includes at least one tubular barrel having a removable cap for providing access to the barrel interior for insertion of a recharge pack. A shuttle disposed within the tube articulates between ends of the tube and interfaces between the soft-sided refill pack and the caulking gun piston. Built into the removable cap is an elongate, coaxial nozzle for distributing the fill material. In a preferred embodiment, two such barrels are coupled together by a spine adapted to hold them in linear alignment. After inserting into each barrel a recharge pack opened at one end, a user inserts one of the barrels into a caulking gun and employs its plunger and piston to force fill material out the nozzle. When that recharge pack is spent, the user reverses the barrels to use the other recharge pack in like manner. The system holds the barrels oriented in opposite directions to minimize interference by the spare barrel with use of the caulking gun. The backbone also may include means on its side for holding a smoothing tool commonly employed by users to smooth a bead of the fill material after it has been distributed from the nozzle.