Make your cannon
Every Catholic church had to have a bell, and the bell-casters produced also the first cannons. Initially, the same technology was used - cannons were poured into disposable clay molds buried in the ground. When naval powers such as the Netherlands, England, France, and Spain established themselves in the 17th century and began building navies with thousands of guns, the need arose to increase the "productivity" of production and to organize calibers. The French regulations from 1689 stipulated 7 different calibers for ship cannons, the British regulations from 1716 stipulated 11 in 28 variants differing in the length of the barrel and the weight of the cannon.