Today, I wanted to look at the different types of hammer-fired handgun actions, and the things that set them apart from each other in terms of manual of arms.
Our assistants today are a GSG 1911, a CZ P-09, an HK P30, and a Taurus PT99. All of these are hammer-fired, but they all differ a bit in their operation. I got all of these from Brownells.
The first thing that we should discuss is the differences some key terms: single action, double action, or double/single action.
Double action is when one single pull of the trigger performs two actions: it pulls the hammer back from rest into the cocked position, and then releases it to go forward and strike the firing pin. Single action is similar, but one pull of the trigger performs just one action instead of two: it just releases the hammer from the cocked position. In other words, the hammer starts in a cocked position and pulling the trigger performs the "single action" of releasing it.
Double action / single action guns are capable of shooting, as their name implies, in either double-action mode or single-action mode. Traditionally, the first shot is taken in double-action, and subsequent follow-up shots are in single action. Additionally, they can switch from single action to double action, usually done through the use of a decocker.
The decocker is a mechanism that allows the user to safely move the hammer of the gun from a cocked position to a decocked position. Decocking is usually done after the weapon is loaded, since pulling the slide back to chamber a round causes the hammer to move to the cocked position. Decocking switches the gun from single action mode into double action mode safely, without the risk of igniting the round in the chamber. Its worth it to note that this is found basically only on double action / single action weapons, because they are the only ones that can switch between the two modes of operation.
So why would you even want a double-action / single action weapon? Why would you ever want to switch the weapon into double action and have to deal with a long, heavy trigger pull? In a word, safety. Having the hammer in the decocked position, and having the resulting double action trigger pull, can aid in preventing negligent discharges. Since the double action trigger pull is longer and heavier, it takes a conscious sustained effort to discharge the weapon. This makes it less likely that poor trigger discipline on the shooter's part will cause a negligent discharge. Additionally, when holstering, the shooter is able to keep their thumb over the hammer, physically preventing it from moving back into the firing position. This helps to prevent the weapon from discharging if, for example, the trigger happens to snag on a shirt or belt while the weapon is going into the holster.
The upside here is that once that first double-action round has been fired, the cycling of the slide puts the weapon into single action, bringing with it all the benefits of the single action's shorter and lighter trigger pull: better accuracy and faster follow-up shots the most obvious of these.
In the real world, the safety and decocker functions on hammer-fired guns come in a various number of configurations, which is why we have rounded all of these assistants today since they give a good picture of how these controls look across a wide number of manufacturers.
On the single-action 1911, everything is simple because there is no decocker at all. The weapon is purely single action and cannot fire with the hammer in decocked position, so all it has are the traditional 1911 thumb safety and grip safety. The trigger releases the hammer, the round fires and the slide cycles, setting it back into single action.
The P30 meanwhile has both a safety and a decocker. They are both located towards the rear of the weapon. The safety is thumb operated, similar to the 1911. The decocker is this small button on the back. When pressed, the hammer drops into the double-action position and the trigger moves forward as well. Again, this lets the shooter drop the hammer into double-action safely with a round in the chamber. This decocker operates separately from the safety, and it can be manipulated with the safety off or on.
Then we have the P-09, which is the only model here with no external safety; it only has a decocker. It is in the same position an external safety would be in, but in this configuration instead of pushing up to activate a safety, you push down to decock the hammer and switch the weapon from single action to double action. Since there's no external safety, the P-09 relies on the longer, heavier trigger pull to act as the primary safety, again since it takes a dedicated and purposeful action to pull that trigger.
Finally, we have the PT99. It is a bit different from the other two double action / single action guns here in that it has a safety but it has no decocker. It can still be switched from single action to double action, but it is done by lowering the hammer manually. My preferred way to do this is to pinch the hammer between the thumb and first finger of the support hand, and then pulling the trigger to release the hammer. When the hammer starts to move, the trigger is also released and the hammer is slowly and carefully lowered to the decocked position. If done correctly, this should allow the hammer to rest in the decocked position where it is not touching the firing pin. With a live round in the chamber this can get a bit sketchy to say the least....this is why you want a decocker.
So that's it: a (relatively) quick rundown of what exactly a double action / single action weapon is, what a decocker does, and how it works in a few different weapons systems. Hopefully that lifts some of the mystery that seems to surround hammer fired weapons. If you're interested in any of these guys, you can check them out at Brownells. That's all I have for you this time, so until next time: stay safe!