"Is the GLOCK SA or DAO? The correct answer is – NO!
That’s right, it’s neither. GLOCK calls it the Safe Action Trigger but that’s just marketing speak. In actuality, it’s a hybrid. The movement of the slide combined with internal springs partially cocks the firing pin, more accurately called the striker. If it cocked the striker all the way, then it would be a SA because all the trigger would do was release the striker to move forward and strike the firing pin. If the trigger pull cocked the striker all the way before releasing it to fire, then it would be DAO. In reality, the movement of the slide partially cocks the striker and the pull of the trigger completes it, so it’s a little of both.
In practice, the GLOCK functions like a SA pistol. The trigger pull is about 5 ½ pounds with a short stroke and a quick reset. That’s SA territory. Also, you don’t get a second strike capability the way you do with a typical DAO pistol. In other words, because the trigger doesn’t fully #### the action, you can’t just pull the trigger again if the round doesn’t fire on the first try. (Well, you can, but it won’t do anything.)
Is it safe?
Which brings us to our second controversy. Since it has a light trigger and requires just a short stroke to fire, people ask, does it really have a safety. Again, the answer isn’t a simple yes or no. It does have a safety. It’s that little lever sticking out the face of the trigger. However, practically speaking, does it do what you want a safety to do? If you want to prevent the gun from firing should you inadvertently pull the trigger, it doesn’t do that. Some pundits say, “well then don’t pull the trigger until you want to shoot something! Duh.” While that’s good advice, it’s just incomplete (as well as ignorant of the vagaries of life). There have been numerous instances of people being shot without intentionally pulling the trigger. In fact, they didn’t have their finger anywhere near the trigger."