going back to the original question of how to remove a stuck ball, one major nuisance is if the gun does not have a recessed breach plug because that allows the ball to block the vent or the nipple channel. A friend brought me two flinters reccently that were dryballed (one by him and one by a person he lent a gun to).
both gun had the vent blocked by the ball, neither gun could be debreached and I was sure that there was no powder in either. My ball puller would not pull the trade gun ball and the other was a 32 cal. I ended up heating area of the barrel where the ball was then smacking the barrel, muzzle down on my chopping block; both cases the melted lead came out. You only have to heat the barrel to about 700F to melt the ball. Also make sure the barrel is pointed in a safe direction just in case the "empty" gun is not.
cheers mooncoon