The Rinella Battery in Malta is home to the largest black powder cannon in the world.
This muzzle loading gun was made to fire out to 8 miles (12.8 km) after then recent advancements in ship design. It fired 17.7 caliber rounds (~45 cm) that weighed 2000 pounds (900 kg).
Video: https://youtu.be/aKmi0PN7LxM?si=lZjs7Kww4St6PVlA
Firing:
Weird that’s it’s a battery gun that measures bore in caliber not inches and caliber which is a multiple of the bore size.
The original web post on Ian’s site has it expressed in inches.
I’m personally more focused on small arms in what I typically learn about, so I just found it easier to appreciate the scale by putting it in a measure relative to the projectiles I usually deal with.
That’s probably why. Most naval guns are bore then caliber a 10" 24 caliber is a 10" bore with a 20’ long barrel.