In 1862, Georgia dentist, builder, and mechanic John Gilleland raised money from a coterie of Confederate citizens in Athens, Georgia to build the chain-shot gun for a cost of $350. Cast in one piece, the gun featured side-by-side bores, each a little over 3 inches in diameter and splayed slightly outward so the shots would diverge and stretch the chain taut. The two barrels have a divergence of 3 degrees, and the cannon was designed to shoot simultaneously two cannonballs connected with a chain to “mow down the enemy somewhat as a scythe cuts wheat”. During tests, the Gilleland cannon effectively mowed down trees, tore up a cornfield, knocked down a chimney, and killed a cow. These experiments took place along Newton Bridge Road northwest of downtown Athens. None of the previously mentioned items were anywhere near the gun’s intended target.
r*ddit
Side by side shotguns kind of do the same thing where they kick slightly to one side or the other. That’s why over/under is the more common double barrel configuration anymore.
The movement is a lot easier to compensate for with a shotgun since it’s easier to control and fires shot shells instead of cannonballs.