Hi Michael,
I think the multi barrel Illustration can be fired, there are 2 different possibilities.
1.Model with separate external vents.
After 3 barrels have been fired, you turn the raster 45 grad and shoot the next 3 cannonballs at the target turn the raster again 45 grad and so on.
same principle as the visser cannon auction at Bonham's Nov 2007.
2.Model where the barrels have internal vents.
All the barrels are fired by a single ignition at the central knot where all the barrels come together. Principle as five barreled flintlock pistol
in the Visser collection. However must say that I don't know where the gunman has to stand without being shot by himself when firing the raster.
best regards