“Don’t try this at home,” Jamie Hyneman and Adam Savage solemnly warn us at the intro to each episode of Mythbusters. “We’re what you call ‘experts’.” Sometimes it’s a good idea to heed your own advice, especially when 1) your advice is not to play with cannons, and 2) you’re actually playing with cannons. Muzzleloading bronze cannon have really impressive ballistics, especially monsters like the 30-pounder the Mythbusters apprentices were playing with.
Muzzleloading cannon were not rated by caliber, but by the weight of their spherical shot. A 30-pound bronze cannonball (that’s 210,000 grains to us gun guys) is almost 6 inches in diameter, and a ‘Long 32’ (a slightly larger cannon with a bore of approximately 16 calibers, or 8 feet) uses 11 pounds of gunpowder to launch it downrange at about 1600 fps.
This generates 1.2 million concrete-crushing, dirt-throwing, hill-hopping, house-smashing, window-breaking pound-feet. Give or take a few hundred thousand.
I always love those Mythbusters ‘Blowing Shit Up’ episodes, but then again I don’t live in Alameda County.
While Savage and his team are still investigating the incident, he said the cannon involved in the experiment was aimed too high.
Yeah, that would probably do it. The Mythbusters were actually damned lucky, because the slightly larger 32-pounder cannon at 8 degrees elevation has a range of more than 1.5 miles. 1.2 million foot-pounds is what ballistics wonks technically call a ‘Shitload’ (or maybe 1.2 ‘Shitloads’) of energy, and it can do all sorts of interesting things.
(As a historical aside, the Master and Commander and Horatio Hornblower books tell us that 30-pounder muzzleloading cannon are enormous guns even by the standards of their day. HMS Victory’s heaviest standard guns in the battle of Trafalgar were long-barreled 24-pounder cannon and short-barreled 32-pounders known as carronades. Two monstrous 68-pound carronades were installed just before the battle.)