Here are some photos of a called leather cannon which I took during my last visit to Germanisches Nationalmuseum Nuremberg, Germany.
Leather Canon calibre 37 mm on a lafette bearing the coat of arms of Paris of Lodron, 1619-1653 archbishop of Salzburg. Germanisches Nationalmuseum Nürnberg Inventory Number W 614. Barrel made of a thin copper tube, reinforced with hemp ropes, wood, leather and iron. Carriage made of wood and iron.
You will find the full resolution images on Wikipedia-Commons
https://commons.wikimedia.org/wiki/F...mberg_W614.jpg