There was a time when this sort of weaponry was common – kind of like land mines, you could set the gun and wait for someone or something to come by and set it off . . . kind of like an assault burglar alarm.
Taken from Kevin O’Brien’s Weaponsman posts:
“Trap guns (which are also called “spring guns,” and other names) were common means of poacher and burglar control from the fifteenth through the 19th centuries. Basically, it’s a firearm arranged to be set up unattended and fired by a tripwire. Such a booby trap could easily be rigged with any firearm and a basic understanding of pulleys, of course, but purpose-made trap guns were cheap and low-maintenance.
Trap guns gradually fell out of favor, especially after World War II as courts came around to the idea that criminals’ rights were more important than victims’. In the USA, the key rulings were Katko v. Briney (1971) and McComb v. Connaghan (1990) in which career criminals (Katko and McComb) were held to be unlawfully killed. At least one other booby-trap dead burglar case was resolved with the acquittal of the booby-trapper, but he used electricity, not a trap gun.
Despite these rulings, trap guns and booby-traps are not banned, per se, in many jurisdictions. But it’s hard to imagine a situation in which an attorney would advise a property owner to deploy such devices. They’re a use of deadly force that is not being used to protect life and limb; they seem to fail several prongs of the use of deadly force test.”
Still, there are a lot of things that qualify as antiques and collectibles – even if they are no longer of practical use.