How does one construct a full auto steel chambered potato cannon?
Given the way the combustion chamber on a spud launcher is set up, it would be easier to make a fully-automatic firearm than a full-auto potato cannon. One *could* get around that by using compressed air, but the pressures required would at best lead to a slow rate of fire and likely require a compressor/air tank at least the size of a Labrador Retriever. The nature of the ammunition also poses a problem as the only way to make it something other than a muzzle-loader would involve some hefty engineering, especially if you wanted it to be airtight enough to have any sort of muzzle energy. If you only want to shoot a spud five feet, go ahead. Otherwise, it’s hefty engineering time. By the time you got done, you would wind up with something that would HAVE to be mounted on a vehicle, or at least a small trailer. And, as Big Daddy pointed out, it would be quite unreliable to boot. You’d be cleaning the thing every 5 shots or so if you’re lucky!