Cannon balls

[adrian]

Stone ball cannons had the chamber narrower than the bore.
Apparently this artillery system disappeared during the 17th century.

Interestingly this system, with a smaller diameter powder chamber, persisted well into the 19th century & was used with shell firing ordnance such as mortars, howitsers & some shell guns etc.

Regarding stone cannon balls, the Royal Armouries experimented with some stone shot from Mary Rose & demonstrated its ability to easily penetrate great thicknesses of timber representing the side of a ship, when recovered the shot was still mostly intact. So the use of lead covered iron shot is rather curious, I think that less wear to the bore than with iron alone was a definite benefit, many of the larger natures of ordnance on Mary Rose were bronze and iron shot would scour this badly, & I would surmise that the intent was to provide for a limited supply of heavier weight of shot than the stone shot.
Much later iron shot were of course used in bronze guns, but with a wood bottom strapped on (later rivetted on) to minimise bore damage.
Adrian