Pot-de-fer

It is believed that the middle of the bolt was likely wrapped in leather for a snug fit, necessary to enhance the thrust from the gaseous pressure within the cannon.

[8] The pot-de-fer was used by the French in the Hundred Years' War in a raid on Southampton and in battles in Périgord, Cambrai, and Quesnoy.

[2] An early reference to the name in French is as pot de fer a traire garros (an iron jug for throwing arrows).

[4] The unusual vase-like shape of the cannon, coupled with the depicted arrow projectile, caused many modern historians to doubt the efficiency — or even existence — of the weapon.

The walls of the chamber were very thick to prevent explosion, leaving a cylindrical bore which was loaded by a wooden arrow with bronze flights (also reconstructed based on archeological findings), of 135 cm length.