As is my usual weird habit, I’ve started wondering: would it be possible to build a functioning cannon out of concrete, or carved out of stone? And what kind of rock would be ideal (or at least, the least-awful) for the latter?
People have built wooden cannons, and even leather cannons—the latter being more of a relatively thin metal gun tube, reinforced and protected by a leather casing—neither exactly measuring up to a metal gun, in terms of overall quality.
But hey, I’m always up for variety, and for getting input on a weird-ass thought experiment. So, could you make a stone gun (say, for the purposes of argument…a six-pounder)—especially without “cheating” and using an inner metal barrel, a la the Leather Cannon above? And how thick would it have to be? Could one be made anything close light enough to be practically aimed—or even transported?