I invented over ten years ago a small device which safely and positively prevents a Glock handgun from firing. It is a small pin that easily inserts behind the barrel hood and merely keeps the slide from closing all the way. The ****** can be removed from a loaded gun quite easily and quickly by a trained and familiar user, but anyone else will have an inert pistol in their unauthorized hands. I have been using this system since 1994, and it works simply and positively. If anyone would like to try one out in any Glock firearm, just send me a private message with your email, and I'll get in contact with you. The ****** is so safe and simple that I cannot wonder at how many unauthorized Glock discharges could have been prevented by my device, the ******, and how many lives could have been saved.