A system, comprising: a projectile launching apparatus configured to clean an inner surface of a tube by forcing a projectile through the tube along the inner surface, wherein the projectile launching apparatus comprises: a) a main body including an exterior surface , wherein the main body contains a breech chamber terminating in an exit port , wherein the breech chamber is provided with a loading port in a side thereof for radially loading the projectile into the breech chamber ; b) a slide disposed over the exterior surface of the main body external to the breech chamber , wherein the slide is axially movable between a first position where the loading port is exposed for loading of the projectile into the breech chamber , and a second position where the loading port and the breech chamber are sealed; c) an air gun operatively connected to the main body in pneumatic communication with the breech chamber ; and d) an exit nozzle connected to the exit port and being connectable to the tube to be cleaned, characterized in that the exit nozzle comprises a nozzle body having a threaded end connected to the exit port and a hose-barb end , whereby: (i) a hose-coupling is secured to the hose-barb end by a first hose clamp , whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp , or (ii) a nipple is secured to the hose-barb end by a first hose clamp , whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher. a) a main body including an exterior surface , wherein the main body contains a breech chamber terminating in an exit port , wherein the breech chamber is provided with a loading port in a side thereof for radially loading the projectile into the breech chamber ; b) a slide disposed over the exterior surface of the main body external to the breech chamber , wherein the slide is axially movable between a first position where the loading port is exposed for loading of the projectile into the breech chamber , and a second position where the loading port and the breech chamber are sealed; c) an air gun operatively connected to the main body in pneumatic communication with the breech chamber ; and d) an exit nozzle connected to the exit port and being connectable to the tube to be cleaned, characterized in that the exit nozzle comprises a nozzle body having a threaded end connected to the exit port and a hose-barb end , whereby: (i) a hose-coupling is secured to the hose-barb end by a first hose clamp , whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp , or (ii) a nipple is secured to the hose-barb end by a first hose clamp , whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher. (i) a hose-coupling is secured to the hose-barb end by a first hose clamp , whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp , or (ii) a nipple is secured to the hose-barb end by a first hose clamp , whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher. <EOS>