Gun Control & RKBA

It's a measure of the force needed on the trigger to fire the gun. With a double-action, that involves cocking and releasing the hammer. With a single-action, it involves only releasing the hammer. With a striker-fired pistol like the Glock, it can vary. With most striker-fired pistols, the striker is partially cocked in its resting state, so it's sort of a "one-and-a-half" action rather than strictly single or double.

The 12-pound Glock trigger arose in the transition period from double-action Smith & Wesson .38 revolvers. Those required a long and moderately heavy pull on the trigger, so cops got used to "staging" them in drawn-gun encounters: They had their fingers on the trigger and were already exerting force on it before they had made the final decision to fire. With the much lighter Glock triggers, this ended up causing unintended discharges.

The optimal solution to the above situation is training: Keep your goddamn finger off the trigger unless and until you're ready to fire. But the NYPD brass, in their infinite wisdom, decided it would be easier and cheaper to have Glock put in 12-pound trigger springs so as to avoid these unintended discharges of the weapon. (Standard Glock trigger pull weight is 4 to 5 pounds.) Here's the problem: It's very hard to hold a pistol securely on target while wrestling a heavy trigger to its discharge point, so accuracy suffers. This explains the extreme low hit rate of NYPD cops in gunfights and why so many innocent bystanders were hit in a recent incident in midtown Manhattan. In other words, NYPD cops' guns are safer when they don't need them, but considerably more of a danger to the public when they do.