Try to figure out why it is stuck (oversize ball, wedge holding it, etc.) Then deal with that first.
As said before, stick a rod down the bore and mark where the front of the ball is to see how much space is behind it. Stand the barrel muzzle up and fill the bore with water. It should seep past the ball and dribble out the touch hole. You can monitor its progress by watching the water level lower down the bore. If the water doesn't drain from the bore, the gun may have been spiked by blocking the touch hole, which will be another interesting exercise to free.