Originally posted by RadZoa
We don't know how fast that cannon ball was going
Well, it's a bamboo cannon filled with gunpowder that fires off clay balls. I'd assume it fires off as fast as a regular cannon. (Considering how close the range was. Just like fletchette guns fire at normal gun velocity from point blank range, and taper off at range due to a variety of factors..)
But if not, the thing's actually existed, so there should be some way of making an educated guess.