> Oh, and civilians can own muzzle-loading black powder cannons. Imagine what someone could do with a 32-pound cannonball.
At many historical locations, said cannons are just sitting around entirely unguarded! Anyone[0] could just come and take one.
[0]...equipped with heavy equipment and maybe a hefty grinder or a stout set of bolt cutters.
They could steal a smaller cannon first and use that on any chains or locks.
They're all plugged with concrete
Concrete plug, steel barrel.
Easily remedied!