I just saw a short video clip which I think is supposed to be of the experiment gone awry. The target (a simulated castle wall made of cinder blocks, I believe) is set up in front of a big dirt berm. Unless the cannon actually tilted upward somehow, seems difficult imagining how the cannonball could ricochet up and over that berm (the original article said the shot missed the wall so it didn't ricochet off the cinder blocks) and still travel 700 yards to that neighborhood. Wow, that will be an interesting accident investigation report to read.