[mauvehaus]

> 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.

[U2EF1]

They could steal a smaller cannon first and use that on any chains or locks.

[tomcam]

They're all plugged with concrete

[esseph]

Concrete plug, steel barrel.

Easily remedied!