I thought about this post a lot before I decided on posting this. In the end, I decided that to keep potentially useful information from responsible individuals because some idiot may decide against common sense would not protect the idiot from finding some way to remove themselves from the gene pool, but would punish everyone else. Knowledge is not useful unless it is shared, so please read the entire post and fully understand what I am saying before you use the information.
This post describes an indication that the Glock pistol is or is not loaded and ready to fire and does NOT in ANY way replace the fundamental safety rules. If you choose to trust this indication and not follow standard safety precautions you can kill your self – or worse – you could kill someone else.
The Glock pistol is striker fired, and the trigger activates the striker by means of a bar connected to the trigger. As the pistol recoils and the slide moves to the rear the striker is recocked and kept at about 40% of the pressure needed to release.
As the slide move forward the trigger bar and spring moves the trigger forward and resets it.
A Glock that has been properly reset has the trigger held about midway in the trigger guard.
If you see the trigger of a Glock pistol against the rear of the trigger guard then for some reason the striker has not reset. This means the pistol has had its trigger pulled but for some reason the slide did not operate. This could mean that someone dry fired an empty pistol, or dry fired a pistol with a dummy round. It could mean the gun has had a misfire or a hang fire that has not cooked off yet.
It could mean the trigger return spring is broken or there is other damage to the Glock internals.
IT DOES NOT GUARANTEE THE HANDGUN IS “SAFE” – It simply indicates something is not normal.
I mention this because as a child I was a fan of Gen Chuck Yeager, and in his book he attributes his long life and success as a test pilot to his thorough understanding of the machines he trusted his life with, and that in several emergencies he was able to fix issues that would have killed someone with a weaker understanding of the airplane.
I doubt you will ever use this to decide that a terrorist is threatening a hostage with an inoperative handgun, or some other Walter Mitty scenario, but it may come in useful at some point so I tell you about this so you can sock it away in your mental filing cabinet for a time you MAY need it.
The Complete Glock reference book, 3rd edition 4th revision.