Single or Double action?
 

The traditional definition of single or double action is based on the trigger and what it does. In a single action gun, the trigger only releases the hammer; one action. In a double action gun, the trigger cocks and releases the hammer; two actions.

Striker fired guns don't have a hammer, but they do have a sear. So, it is logical to see it as setting and releasing the sear.

The Glock trigger actually pushes the striker back a little as the trigger is pulled. Thus, I can see how it could be considered a double action only. The M&P however, only releases the sear. The striker/sear is set by the action of the slide. To me, since the trigger only does one thing, it's a single action.

To confuse things more, several of the M&P models are described as "double action only" on the S&W website.

So, which is the M&P? DA or SA? What do you think and why?

Neither, I would just call it a "striker fire trigger". But I'm fine will calling it a DA (even though it's technically not). Striker fired triggers don't feel anything like a true DA trigger IMO. And they sure don't feel like a SA trigger. Okay, maybe they feel like a really ****** SA trigger.:D

I think SA because pulling back the slide is similar to cocking the hammer.

Single action because you can't pull the trigger a second time without racking the slide (Just MO):rolleyes:

I think they claim DA because of the hump on the sear... I ground mine off so does that make it SA?

What "hump" are you talking about? My sear has no such feature.

I say SA because all the trigger does is release the striker, it doesn't reset it in any way.

That should read as follows:

To clarify things, several of the M&P models are described as "double action only" on the S&W website.

If it quacks like a DAO Glock...

/thread

Then you don't have a factory sear? It is the little extra bit where the striker engages...
http://i38.photobucket.com/albums/e1...DSC_0303-1.jpg
(Photo stolen from this sight)

OK, I see what you're talking about. Your definition of a "hump" and mine vary greatly.
"It's Frankensteen": Dr. Frederick Frankenstein meets Igor for the first time. - YouTube

Even so, that makes absolutely no difference to how the trigger works. Still only performs one function.

Pulling back the slide is not like cocking a hammer.. When the M&P goes to battery "this forward movement" of the slide that sets the striker. George

Cocking the hammer and moving the slide both set the sear. I see it as the same kind of action.

Huh?:confused:

Disagree George you can't push it fowward till you pull it back. Besides, I said similar.

Yes I agree about the sear! But some don't seem to see that the striker is set or "cocked" only when the slide is in full battery from that forward movement of the slide. I myself consider it a S/A gun.. George

Rgoodwin,
Sorry! Yes I agree we came to the same conclusion S/A!

Hammers and strikers do the same thing. They are spring loaded objects that store energy then transfer it into the primer. DA is when the trigger cocks the spring loaded object then releases that spring loaded object.

Single action is when the trigger is not capable of cocking the "spring loaded object". I would say because the trigger only performs a "single action" (releasing the sear) that the gun should be called single action.

Well said! George

Agree 100 percent! Great explanation !

While we are on the trigger subject I gotta tell you guys what's happened with me and my FS 9. My trigger spring broke at the big hook. Sent S&W an email about two weeks ago very explicit about what part broke. I got an email back very quickly that said they would place it on back order. 6 weeks to get one. I stewed for a week and sent a response to their email which contains my email and all the particulars about what I need. Again they responded within 5 minutes that they shipped the part. Great, except today I get a package in the mail and its pretty big. I open it excitedly thinking hey they sent me a FS mag too. But no I'm frowning cause they sent me 2-15 round 40 mag springs instead. I've contacted them again. We'll see how this plays out. Sorry to hijack your thread just had to vent. Still love the brand just ready to be back in business.

i voted single action, because the trigger only performs one function. On a M10 revolver, for example, the trigger performs two actions. Releasing the cocked hammer, or in a DA stroke, cocking the hammer and then releasing it.

I ground mine off as well. :D I would say it was always SA. I'm thinking that if you measure from the pivot point to the tip of the hump vs that same distance without hump the results are negligible.

I think the point was added to define a specific amount of surface area contact and not to further retract the striker during the trigger pull. I could be wrong about the intent...

Either way it requires a nice polish job anyways.;)

I think 99.98% pre-cocked vs 100% pre-cocked is not enough to claim DA.

I can guess this one, the term "single action" can have a very negative affect on some people, who might think that single action and 'hair trigger' mean the same thing. The uninformed (including some police chiefs), think that single action and unsafe are terms that go together'

"double action" on the other hand is synonymous with a long, hard trigger pull, which some might take to mean that it is safer, less likely to go off by "accident."

Nicely said Don. Yes, I believe it's either legal or marketing reasoning for saying that they are Double Action only.

Of course, I find errors on websites all the time. It's entirely possible that whoever made the site was ignorant of what it means.

Much like the Senator who thinks magazines are only used one time and has a say so in new gun legislation!

I say M&P is DAO because ATF says so. :)

That said, it is more like a SA because pulling the trigger releases the cocked firing pin without pulling it further back before release as with the Glock. I believe the S&W is closer to the Springfield XD in that regard.

The biggest lie told by S&W is that their M&P pistols are double-action. They base this on the striker moving a micro inch backward during the trigger pull. Meanwhile, Springfield Armory pistols that use the same approach are labeled single-action.

Compare that to a true double-action striker-fired pistol, the Glock or Walther PPS that have a half-cocked striker prior to trigger pull.

yes they do :)

I'm so confused ........ :D

I don't see the confusion. Take a double action auto and pull the trigger on a dead round, it doesn't go bang, if you pull the trigger again, it will hit the primer again and it may go bang (or not). Do the same thing with a M&P, what happens when you pull the trigger the second time..... nothing, you might as well wave your finger in the air. I see the reason for the long trigger travel in a M&P environment but to me the definition of a double action firearm is "self cocking" which means a full recock from being fired (or attempted firing). To me a microscopic rearward movement of the internals doesn't come close to what I would call a cocking action. I like my M&P a lot but wish it was a DA so that in the rare occasion that I get a failure to fire I could hit the primer again before racking it out on the ground.

I agree,
Sorry for the comparison but take a Ruger LC9 that is called D/A only gun.. But you don't have a second strike on a dead round without racking the slide some.. It's half cocked in it ready position pull the trigger and that's it you can't just re pull the trigger it takes a little racking of the slid to reset it back to half cocked then it D/A.. I believe the M&P is a S/A gun too..George

As I see it SA or DA in a Semi Auto only applies to the first shot, the rest of the rounds are fired semi automatically from a cocked hammer or striker. So it's the the actions that the shooter need to preform in order to fire the gun when racked that will determine SA vs DA. In other words do they need to cock the hammer after the gun is racked.

Colt 1911 rack slide, lower hammer,or put on safe. To fire cock hammer or release safety and fire. Most all consider this a SA gun but if one leaves the hammer back is it then DA?

CZ75, Rack slide, either lower hammer or lock hammer in place, in either position a pull of the trigger will fire gun when safety is disengaged. Most all consider this a DA gun.

MP or Glock, Rack slide, pull trigger gun will fire. As with the CZ 75 no other action is require after racking the slide to fire gun from a carry position safely.

If we are talking revolvers the answer is very straight forward, after loading gun do you have to pull hammer back in order to fire? If so SA if not DA.

I don't understand the confusion either. Aside from variations such as DA/SA;

If the hammer (or striker) is at rest (or partially at rest, a-la Glock) following the action of the slide, and the action of the trigger fully cocks the hammer (or striker) and then releases it, the gun is a double action. The trigger cocks and releases the hammer or striker, two actions, hence "double action."

If the hammer (or striker) is fully cocked by the action of the slide, and the trigger/sear releases it, the gun is a single action. The trigger only releases the already cocked hammer or striker, one action, hence "single action."

The M&P, (or at least the Shield) is SA.

Yes that's how I see it too! George

I consider the Glock 1-1/2 action.

Tom I see what you mean.. Ya a true D/A gun IMO as long as you keep squeezing the trigger the hammer moves back and the is released to strike the primer even if it's the same primer.. Having to pull back the slide any amount to set a hammer or a striker even on a Glock or Rugger LC9 "wife has one" for me also makes it a 1 1/2 action gun.. George

I still think the type of action only applies to the trigger. If it does one thing, it's a single action. If it does two, it's a double action.

Striker fired dao pistols work with a partially cocked striker, and the trigger fully cocks and then releases the striker(ie Glock). I voted double action because I didn't understand the exact inner workings of the M&P, now if I had it to do again, after reading this thread I would vote single action.

Question for Tinn-Can about sear modification.

Very interesting--how does this feel now? Is it smoother, easier to control? Do you think it could be too easy, I mean, dangerous to carry?

Striker fired! To put striker fired weapons into DA or SA categories is very antiquated, they belong in neither.

I used to work at a department that required that all duty weapons be double action. DA/SA was ok. When I was new there, I pointed out to another officer that lots of the guys carried Glocks but Glocks are not double action. He told me not to dare mention that to the supervisors because they would not understand what I was talking about and they might disapprove Glocks because the Chief liked DA/SA Sigs. Glock does not call their system double action or single action. They call it "safe action". I guess S&W decided to call theirs DAO because "safe action" was already taken and "unsafe action" or "long mushy trigger pull" was not as marketable.

I know another administrator that gets the heebie jeebies everytime he sees someone carrying a cocked and locked 1911. The difference between a 4 pound trigger with a manual safety and a grip safety versus a 5.5 pound trigger pull with no manual safety is beyond his comprehension. Just like Brownings 1903 32, 1908 380 and 1908 25 ACPs, nobody gets excited when they are cocked and locked because you cannot see the hammer. Since you can't see that a Glock or M&P is cocked and unlocked, it is ok. Just like a double action revolver, if you have a round in the chamber of one of these autos and you pull the trigger (intentionally or unintentionally) it is going to go bang 99.9% of the time. The trigger pull is just much heavier and longer on the revolver (unless you have a NY trigger in the Glock).

S&W probably lists some of the M&Ps as DAO for marketing. They know that it doesn't make any difference as far as safety is concerned. So, they play on people's ignorance to sell to markets where they want DA guns.

Like I said earlier, it doesn't matter if it's a striker or hammer gun. The type of action is determined by the trigger. The trigger only does one thing so, single action.

I believe you have it correct here. It is vital to the success of any pistol sold to LE that it be "double action only," as it was long ago decided by police administrators that single action is dangerous.*

*It is generally this same crowd who actually think the .357 SIG caliber is, ballistically, a .357 Magnum, not a 9mm +P+. :)

it's neither

The trigger's one job... move the sear that releases the striker. It does not cock the striker any further. It doesn't cock the striker at all. If anything it does move the striker back a ridiculously small amount. I would say on a 1-10 scale of closeness to single action, it get's 9.5 in my book.

Well, that's certainly a unique perspective.

What are you telling us? That it's a 0 action? The trigger has no function? Or maybe a triple action?

Or are you just trying to be funny?

I asking a serious question here. If it's neither, what is it?

There is no confusion. It is as stated, by the manufacturer - double action.

Please explain? I believe they are only saying that. I believe that they are playing on the ignorance of the buyer to get past things like department regulations so they can sell it.

Some departments require the DAO for a safety reason. The M&P is safe.

So, tell us why you think it's a double action.

The M&P is a single action? Oh my goodness, I've been carrying a "cocked and unlocked" firearm.

It's neither. In single action, you pull the trigger just a hair, [3-5 lbs pressure] & the gun fires. In double action you pull the trigger an inch, [10-12 pounds pressure] & the gun fires. Neither of these describes the trigger on a striker fired pistol. I choose to use Glock's description. "Safe action".