Potato
Some standard potatoes.
The potato (aka spud) is the original and most common ammo for a spud cannon. This is largely an effect of their low cost and availability. Typically large and juicy ones are preferred, as the size is needed for larger barrels and the juice acts as a lubricant in the barrel when muzzle loaded. They also have the advantage of forming a nearly air tight fit in the barrel when cut to size with a muzzle knife or spud cutter, which can prevent loading and thus be an inconvenience at times; see muzzle loading for solution.
The density of a potato (as expected from a foodstuff) varies, although it is typically around 1.1 g/ml (16g or .58oz per cubic inch)
