single or double action

[Jerry]

Can someone please explain to me what the differance is between a single or a double auction is? Thank you
Jerry

[Old School]

In order to fire a handgun, two specific actions must take place. Step 1: The mainspring must be compressed to generate potential energy. This is often done by cocking the hammer. Some handguns, however, do not have hammers, and the mainspring is directly connected to a spring-loaded striker (the firing pin). Step 2: The mainspring must be released, converting the stored potential energy to mechanical energy. All handguns (revolvers, semi-automatic pistols, and Derringers) must perform these two steps in order to discharge the cartridge. The action of a handgun refers to the mechanism used to perform these steps.

There are three general types of actions commonly used on handguns, each performing the two basic steps slightly differently.

Single Action
When the trigger is pulled on a single action handgun, it performs only Step 2 -release of the hammer from its cocked position. In single action handguns, the hammer must be cocked manually (Step 1).

Double Action
When the trigger is pulled on a double action handgun, both Steps 1 and 2 are performed. The hammer is cocked and then released by pulling the trigger. Since the process of cocking the hammer compresses the mainspring, the force that must be applied to the trigger of a double action handgun is greater than that of a single action gun. The hammer of a double action handgun, however, can be manually cocked.

Double Action Only
Double action-only handguns function essentially the same way as double action handguns, except it is not possible to manually cock the hammer.

[Jerry]

Thank you for your time there and your reply.. So an XD is a single action?

[a911scanner]

Jerry,

While I was a little fuzzy on this myself, your answer is right there,...if you're familiar with the XD's

Double Action Only
Double action-only handguns function essentially the same way as double action handguns, except it is not possible to manually cock the hammer.

AFAIK There is no manual hammer on an XD. I have the SC-9, and most of the pics I've seen around here are of harmerless XD products.

Mark

PS Anyone else that knows more than myself (of which there are many) please correct this statement if it's wrong.

[jdavionic]

Originally Posted by a911scanner

Jerry,

While I was a little fuzzy on this myself, your answer is right there,...if you're familiar with the XD's

Double Action Only
Double action-only handguns function essentially the same way as double action handguns, except it is not possible to manually cock the hammer.

AFAIK There is no manual hammer on an XD. I have the SC-9, and most of the pics I've seen around here are of harmerless XD products.

Mark

PS Anyone else that knows more than myself (of which there are many) please correct this statement if it's wrong.

He's correct. All XDs are DA (double action only).

[[TASF]Overkill]

With the exception of that tiny amount of rearward movement the striker makes when you pull the trigger, isn't racking the slide the same as "cocking" the gun?

I would think that would make the XD single action. Can't fire unless it's cocked first. Either you cock it, or the blowback action cocks it.

However, I KNOW the XDs are deemed "DAO". Just not sure why.

[billwing]

Ajames addressed this topic in a FAQ thread.

Is the XD double or single action?
The XD uses what SA calls a USA Action Trigger System. This trigger is in reality a single action trigger by definition since the XD when cocked, the firing pin is fully compressed and when you pull the trigger it releases the firing pin. Now to be fair to the XD its trigger is designed to have what feels like a military two stage trigger. The XD has a smooth long take up and then hits an area where a little more force is required and then a crisp trigger break. The reset of the trigger is also long, so during the triggers travel it mimics a double action with a trigger pull of about 4-5lbs.

[Delija]

Originally Posted by [TASF

]

However, I KNOW the XDs are deemed "DAO". Just not sure why.

Not sure where you are getting this info.

The XDs are single action, with a trigger that has a "double action" feel as Old School explained.

The XD is always cocked before the trigger can be pulled (effectively)which strikes the firing pin which in turn hits the cartridge's primer...either by racking the slide manually to chamber the first round, or by the firing of the gun which causes (by blow back) the slide to be racked which cocks the hammer and sets it to be released by pulling the trigger. Since pulling the trigger does nothing to cock the gun, it is a single action gun.

Waki Qiwebis,
D.

[mcb]

I agree with those that say the XD is a single action only pistol. No matter how the trigger is made to feel the gun's action functions like a single action only handgun. Even though the trigger has a double action only feel, the striker and sear function as a single action only. If it was a double action handgun then an operator could repeatedly pull the trigger to strike a faulty cartridge multiply times without manually resetting the striker. This double action function of multiple strikes is not possible with an XD. We all know that you must with draw the slide back manually to reset the striker. This is single action only no matter how much the the trigger may feel like a double action trigger.


Ramblin
mcb

[JD McDorce]

Wheelguns are usually easier to classify than modern semi-autos. A pure Single Action is along the lines of a Ruger Blackhawk, where the hammer needs to be manually cocked prior to firing. Most exposed hammer revolvers are DA/SA in that they can be fired in double action mode (where a long pull of the trigger cocks the hammer, then releases it) or single action mode (manually cocking the hammer). Shrouded hammer wheelguns are somewhat of a classic DAO, since the hammer cannot be manually cocked back and rely on a full stroke of the trigger to cock and release the hammer.

Hammer-fired semi-autos become a little more complex when it comes to SA and DA (although DAO's really aren't that much different than a shrouded hammer wheelgun), in SA or DA typically refers to the manner that the first shot is fired. Cycling the slide (such as to chamber a round) on most hammer fired semi-autos cocks the hammer, placing the gun in a single action condition. Those capable of DA first shot capability typically have a decocking mechanism to place the gun in DA mode. For subsequent shots, the hammer is cocked by the cycling of the slide. Since the hammer is already cocked, single action tends to refer to only releasing the cocked hammer for firing. DAO's, in theory, only allow the hammer to be cocked through pull of the trigger, regardless of cycling of the slide.

If one assumes that a striker performs the same function as a hammer, SA and DA logic would tend to follow. Where much of the debate still lies (particularly for those familiar with IDPA rules) is how the most popular striker-fired handguns are classified. Without getting into the squeeze-cocked HK's, the lack of any kind of device to "decock" the striker on a striker-fired gun would theoretically result in a classification as either SA or DAO. Complicating the debate is how "partially cocked" versus "fully cocked" figures into things. That said, I find it difficult to try to lump the action of an XD (or a Glock) into the category of being a SA or DAO, with the complexity of a USA or "safe action" driving it into a separate category on it's own.

mcb's comment regarding repeated trigger pulls raises an interesting point - are multiple strikes possible with a Glock?