Last edited Fri May 13, 2016, 09:54 AM - Edit history (1)
... as well as some others.
Unlike "smart guns," these are proven technologies. However, their utility as safety measures is questionable.
First of all, with many semi-autos, you can see if there's a round in the chamber simply by looking at the ejection port: the edge of the cartridge rim is visible at the back of the chamber. Instead, the laws mandate some kind of warning button, usually red in color, that pops up when there is a round in the chamber. However, the user still must look at the gun, or the red button can go unnoticed. There has been at least one lawsuit charging that the warning device wasn't sufficiently noticeable, leading the plaintiff to fire the gun anyway. It's hard to see how such idiocy can be avoided, short of a Nerf hand that pops up and bops the user in the face if he/she touches the trigger, possibly with the addition of audio screaming "Hey, moron, there's a round in the chamber!"
Magazine-disconnect safeties are another attempt to idiot-proof semi-autos, using technology to avoid the possibility that the owner of a semi-auto pistol doesn't know that a round in the chamber doesn't come out when the magazine is removed, nor that racking the slide with a loaded magazine in place will put another round in the chamber. The drill to unload a semi-auto is always "remove the ammunition source, then clear the chamber." At best, magazine-disconnect safeties prevent idiots from shooting themselves when they think they have unloaded their gun. At worst, they could enable accidental shootings when the idiot owner leaves a round in the chamber, thinking the gun is safe because the magazine has been removed, and then someone else (or the original idiot, at a later date) comes along, inserts an empty magazine, and pulls the trigger because "Hey, it's an empty gun, right?"
The bottom line is that both scenarios are based on someone violating one of the most fundamental rules of gun safety: You do not pull the trigger on a gun unless you (a) are intending to fire it or (b) are absolutely certain there is nothing in the chamber.