These things have been around for a while. Yeah, they’re just small plastic thingies that replace the back plate of the slide. I’ve never seen one of these things in person, but I assume installation is just replacing the back plate, which takes all of one minute and requires no tools.
Legally, in China: these are probably just pieces of plastic in China, not regulated, or else the regulators don’t care. Legally, in the USA: the thing itself is a machine gun. It could be created and possessed by a SOT, with the right paperwork. Post May 1986, no such things can be made that could be transferred for private ownership. Violation is a serious Federal felony, plus likely state felonies as well. Note that this applies to the thing itself, even if it’s not attached to a gun, even if the person doesn’t have a gun.
Practically: someone with some practice, and a full-sized Glock 9mm, and the 30-round mag, could use these effectively to deliver bursts. Practically, on any other Glocks, like the 26 etc, with standard sized mags, and without practice, this thing will result in bullets spraying wildly and an empty mag. If I had to choose between being assaulted by a random criminal with a Glock, and the same guy with a full-auto Glock, I would strongly prefer the guy with a full auto Glock, because he would be out of ammo and hit nothing within one second, and then it would be my turn to deliver controlled, aimed shots.
Failed Internet ad monitoring: about a year ago, Youtube kept on showing me ads for “solvent traps”, which are these little screw things that would allow one to screw an oil filter to the screw end of a barrel. These little screw things sold for a few dollars and are made in China. They are also likely to be considered unregistered suppressors by the BATF and are basically the same felony as a machine gun, although unlike a machine gun, it would be possible to do proper paperwork (depending on state law) and possess one. Every knowledgeable gun owner who sees these things (solvent trap adapters, Glock “airsoft” full auto switches, whatever) knows they are one credit card checkout away from an online felony.
As others have pointed out, many other semi-auto guns can be converted pretty easily to full auto, but it seems like the Glock design is the easiest to do in a practical way. The only way to really stop people from having any practical chance of gettnig a full-auto gun is to limit guns to things without any gas or recoil mechanisms, ie, bolt action and break actions only. But as I said above, if criminals actually put these on their guns, they will make their shooting far less effective, and also tack on a federal decade to whatever else they’re doing, so in some ways this whole thing is a trap for the stupid rather than a risk to the normal.
The workers that do ad content approval just don’t know about these things. Which is perfectly understandable.
