I collect rare artillery books as a hobby. One of the books I have titled GUNS An Illustrated History Of Artillery, printed 1971 states this: "Red-hot cannon balls were fired day and night during a siege, with the intention of setting the enemy's stores alight. As in the illustration below, the shot was heated until cherry-red. A powder charge was inserted and rammed down, followed by a wad of damp hay or clay. The gun was aimed, the rounds dropped down the barrel with tongs and the gun fired immediately to avoid the heat setting off the charge prematurely." A few things come to mind with this. The wadding of anything damp is not by modern standands considered safe practice and "firing the gun immediately" IS firing the gun prematurely. Dom.