DAO?

[TexasRaider]

Was a good descriptive post on the DAK trigger system until we got here. Several striker-fired guns have "restrike" capability including the Taurus PT-111G2, PT709, et al.

I stand corrected. Granted, I should have more accurately stated the Glock, M&P and P320 platforms, which are probably the most mainstream and popular striker fired systems right now. Admittedly, I have had little experience with Taurus pistols, aside from a the old PT92. Thanks for the correction.

 

[ghoffman]

Thanks guys, What a great discussion, its amazing what you can learn if you just ask! I had the Oregon game on the TV but didn't see any of it. I can however, tell the difference between DAO and DAK trigger systems!!!

 

[Rastoff]

In my words, the LEM is a DA/SA without a decocker.

Semantics. Like I said, there will always be those that disagree. That's OK, it's more important to understand the trigger than to agree on what it's called.

The LEM is by definition a DAO (see post #5). The trigger cocks and releases the hammer every time no matter what.

McE, your assessment is correct. Drop the hammer on an empty chamber or a dud and the mainspring is not set by the slide and must be compressed by pulling the trigger.

The difference from a DA/SA is in how the hammer works. A DA/SA left in SA has a fully cocked hammer. If the sear were to let go, the gun would fire. In the LEM, the hammer is down. If the main spring is released, the gun won't fire. Every gun, unless it has a trigger block like the M&P or 1911, will fire if the trigger is pressed. The type of action is completely irrelevant.

Is one action safer than another? This is another subject that causes endless and pointless debate. The type of action isn't listed in any of the 4 basic rules of gun safety.

 

[McE]

I'd really like to find out if the LEM would fire IF
-firing pin block was defeated
-internal "unseen" part of hammer gets released

When you say "In the LEM, the hammer is down.", it's half correct. The top part of the hammer is indeed down, but the lower part is still fully cocked.
It is entirely possible that if the internal hammer was released (main spring is released, as you say), it would still have enough force to fire a round as it runs into the resting top part of the hammer (again, if the firing pin block was defeated).

I can't speak with the certainty that you speak with, about how a DA/SA hammer being dropped (ignoring firing pin safety) would definitely fire whereas the LEM experiencing the same condition would NOT fire. I think it might, I'm not so certain that it wouldn't as you are.

 

[Bounty]

I stand corrected. Granted, I should have more accurately stated the Glock, M&P and P320 platforms, which are probably the most mainstream and popular striker fired systems right now. Admittedly, I have had little experience with Taurus pistols, aside from a the old PT92. Thanks for the correction.

No harm no foul brother...just wanted to keep those who would have read that statement and accepted it as blanket doctrine from getting confused.

As I stated, great description of the DAK trigger. I'm sure many here would not have had the necessary experience with it to provide the comparison data point.

 

[Rastoff]

I'd really like to find out if the LEM would fire IF
-firing pin block was defeated
-internal "unseen" part of hammer gets released

I think we'd both agree that these guns are crazy safe. So many things have to be defeated that the guns simply won't fire without human intervention.

However, if the firing pin block was defeated and the main spring were released, rotating the inside hammer bushing, I'm 100% positive the gun wouldn't fire. There are two reasons for my confidence. The first is the simple fact that there isn't enough momentum in the internal bushing, without the hammer, to overcome the firing pin return spring, and send the firing pin into the primer with enough force to ignite it. The second is the aspect of the H&K USP you forgot, the hammer block.

The H&K USP LEM works like this:
When the gun is fired, the slide cocks the main spring. As the trigger is released, the hammer follows it down. There is a hammer block similar to the half-cock position on a 1911. This block keeps the hammer back about 1/16" from the firing pin. This gap will prevent the gun from firing even if the main spring were released.

So, for the H&K USP LEM to accidentally discharge, the sear would have to fail, the firing pin block would have to fail, the hammer block will have to fail and the force delivered to the firing pin will have to be enough to overcome the firing pin return spring.

Just to keep this on track, all of this has nothing to do with the terminology used to describe the trigger system. You may call it what you like.

 

[McE]

It would seem then the DA/SA has the same benefit of a hammer block, as the falling hammer would fall to the position it would as if you were to use the decocking lever to drop it.

You're absolutely right that a lot of safeties have to fail for an accidental discharge without a trigger pull. That's largely the reason I think keeping a DA/SA in SA in the holster is no more dangerous than the LEM, but you get a nicer trigger every single pull. No one seems able to process the idea of carrying a gun SA with no manual safety in a holster, it's just unanimously denounced as a bona fide idiot move (until it has a hinged trigger, I guess).

Just a purely hypothetical rumination, I'm still curious if the released internal hammer of the LEM is enough to ignite a primer, assuming the rest of the system is ready to go. I just don't see the visible half of the hammer being responsible for all that much inertia to actually bring the total force below what's required for ignition.
It's as if you somehow secured a nail to a hammer and hit it into a board (DA hammer dropping), vs holding the nail to the board and swinging the hammer separately. The weight of the nail (i.e., visible LEM hammer) is just a fraction of what's being brought by the hammer (i.e., hammer spring force).

 

[Rastoff]

No. The inertia of the hammer is much greater when coming from full cocked vs already down.

Your analogy is flawed. In it you still have the full inertia of the hammer head for either scenario. Instead, modify it to say a nail is partially inserted. Now hit it like normal with the hammer. Then rest the hammer on the nail, but now strike the hammer handle just above where your hand is holding it with another hammer. This is what it would be like for the inner bushing on an LEM equipped H&K. Dramatic difference.

Here is a picture of what I mean:

If you hit the hammer with anther hammer where the arrow indicates, it won't drive the nail very far. However, swing that same hammer and you get a lot more inertia working for you.

In each case you have the same mass hitting the nail, but not the same inertia.

 

[ghoffman]

I got a chance to shoot a SIG P226 40 cal DAK last weekend, one of the LEO/owners of the range was very kind and let me run through a couple of mags. What a nice gun!!! One thing I realized right away, the double reset on the DAK would make it harder to shoot the Shield. With the SIG you release the trigger PAST the first reset and I've already got the muscle action going for one reset. I would buy this gun on the spot if the "inside" reset was gone! Another issue for me: getting to the second reset seemed to take forever. I'm afraid I'm a M&P person! I still want to fire the SRT trigger system before I make a decision but I'm going to have to get really lucky to find an opportunity to shoot this one! The M&P Performance Center CORE has the feel I like but I don't need all the fancy optics. I'm leaning towards a 5" 9mm Pro with an Apex trigger. sear, striker, and springs. I have them on the Shield and I really like the way it feels!
Feel free to tell me what you think - there is a couple of hundred years of experience on this forum - I'm all ears!

 

[TexasRaider]

Hey, whatever you feel best with, go for it. There's a reason Baskin-Robbins has 31 flavors!

 

[McE]

Not a fan of the DAK myself for similar reasons. Had a P239 DAK, shot it pretty well but it requires its own familiarity. Reading up on the history, I got the impression that it was more of a bandage to a troubled trigger design. They started with a trigger that would lock up the gun if you didn't fully let out the trigger (short stroking after feeling the false reset), so all they did was make it so a short stroke would still fire the gun, but they said don't rely on it, it's a 'just in case' 'feature'. Just couldn't stay on board with the Sigs after all of these bandaids they marketed as revolutionary.

 

[Pondoro]

Striker fired pistols and single action pistols both store energy in a spring. The striker fired pistol removes the visually scary cocked hammer.

You can build either gun to have a long light trigger pull or a long heavy trigger pull or a short light trigger pull. Modern striker fired pistols have a long trigger pull, and the weight varies.

Trigger pull weight is a combination of overcoming friction plus compressing the spring or springs. People buy after market kits to change the weight.

Forcing the trigger to add some level of cocking force to the striker spring is a convenient way to make the trigger pull a bit heavier.

Stated a different way - the action of the slide re-cocks the hammer or striker spring "100%" in a single action gun, re-cocks the spring zero percent in a double action gun, and re-cocks the spring to an intermediate level in the modern striker-fired guns. The manufacturer chooses that percentage.

A goon in a big-box outdoor store tried to tell my daughter that a concealed hammer revolver was "striker fired."

 

[TexasRaider]

McE,
My understanding of the DAK trigger and its history is not the same at yours, but I taught many folks to shoot it, and I've found that, once understood, it really is a very good system that can be shot fast and accurately, but admittedly it's although not for everyone.

It does have its own unique style, but then so does a striker fired system. Personally, I find striker fired pistols uncomfortable to shoot because of the lack of 'feel' that accompanies their pull, making them feel very uncommunicative to me, like driving a go kart - wound up way too tight with an predictable over-responsiveness I don't care for. I'd rather have communication between me and machine, where I know what it's doing, how it's doing it and can fell the process as it's happening. Glocks and other striker fired pistols feel like 'over clicky' toys that don't talk back.

Just my opinion.

 

[McE]

Sigs are in the same class as HKs, in that they have a longer trigger reset than necessary (for most of our uses). I'm certain it's a design aspect in the name of 'reliability'. More leeway in the range of motion for things to function. The 92 however has a shorter reset so maybe Sig and HK just gave too much of a margin than they could've gotten away with.

The M&P has a reset point that coincides with the break point (sear release point). That certainly spoils anyone trying to compare it to hammer guns that have a trigger reset maybe 1/2" past that break point.

 

[TexasRaider]

Heh, I think your feelings about Sigs became pretty clear by using reliability in quotes. Fair enough, no one is obligated to love every weapon.

However, the M&P reset hardly spoils any debate against it. It is simply another style of trigger. If anything has been 'spoiled', at least in my experience, it is the reputation of the M&P due to it's lack of quality. A thorough testing of that weapon by my agency led to it's being dropped immediately and with extreme prejudice, while the Academy that using was in still progress. A shockingly high number of failures in ejection, feeding and firing, on many, many pistols, clearly pointed out that S&W's polymer option is no real option at all. They were issued DAK Sig P226's, as the rest of the Dept has had since around 2004, to great effect and with no issue.

I know others may have different experiences, but I've observed and participated in tortuous testing of Sig's since 1989, and no one who rightly calls themselves educated in handguns would question the reliability of Sig Sauer's classic P series pistols. The trigger's may not be someone's cup of tea, but questioning their reliability only damages one's own credibility.

The same cannot be said of one questioning S&W's current reputation for reliability in the M&P line. I believe mine is not the first agency to test, reject and return those pistols for being, quite simply, unacceptable in terms of 'officer safety' reliable.

 

[McE]

Oh I was definitely not saying Sig's weren't reliable, just saying they may have just overdone the ensurance of reliability when they would not have lost any reliability with a little less trigger travel for reset.
I know the P226 is a great pistol, it almost stands alone nowadays if you're looking for a metal gun. I'll admit I haven't kept up with all of their trigger acronyms lately, so maybe there is some combination of short reach/reset/light pull variation that would erase my distaste for the DAK's "short stroke this trigger at the once-false-but-now-somewhat-true-reset and you'll have a heavy pull so try not to short stroke this trigger" approach.

 

[ggibson511960]

Safe Action

Seems I recall Glock or S&W or both calling their firing mechanism "Safe Action". My opinion is that the S&W M&P trigger action is SAO with a striker instead of a hammer. Your trigger finger and the primer don't know the difference. The trigger pull is not all that long, certainly not as long as the double action pull on a Colt or S&W revolver. It is heavy and creepy through its short actuation and has a ton of backlash after release. It also has a hinged trigger lower lever to make sure that something is inside the trigger guard pulling the trigger, hopefully your finger. To me, it's like a Luger with more backlash. If you study the trigger bar and sear, there isn't much cocking energy being put in that striker by the M&P trigger pull. The angles are such that the trigger must move the sear through a goodly distance to disengage the striker sear. Technically speaking, any single action trigger puts a small amount of additional energy in a hammer or striker by virtue of the engagement angles. If it didn't, the hammer and trigger sear would not relax to a safe position after a partial pull and release. Some don't after sloppy manufacturers and gunsmiths smooth off the sear surface. M&P's are tremendous weapons but the long backlash forces good trigger technique to keep from pulling shots off line. Nobody is going to be competitive at bullseye or metallic silhouette with one, but that's not what they're for.

 

[ghoffman]

I think the way to go for me is the P226 DA/SA with the SRT kit installed. I can get the P226 Nitron DA/SA for a hair under 800.00 and 50.00 more for the trigger kit. Install doesn't look any worse that the Apex Duty/carry kits and I'll have a target pistol with a nice short reset and a long sight radius. Might actually pay a smith to do the install just to preserve the lifetime warrenty, but even the factory install is less then 150.00. When I shot the 40 DAK I realized right away that this is a very nice gun, I just didn't like the double reset, especially because the travel was ridiculously long. The SRT kit sure looks like the answer. Speaking of answers, thanks you guys - I asked about DAO and I get schooled about DAK and LEM and SRT - l love it! Looks like a Shield in the holster and a SIG at the range - not too shabby!!!!!

 

[TexasRaider]

Oh I was definitely not saying Sig's weren't reliable, just saying theyisn't ine just overdone the ensurance of reliability when they would not have lost any reliability with a little less trigger travel for reset.
I know the P226 is a great pistol, it almost stands alone nowadays if you're looking for a metal gun. I'll admit I haven't kept up with all of their trigger acronyms lately, so maybe there is some combination of short reach/reset/light pull variation that would erase my distaste for the DAK's "short stroke this trigger at the once-false-but-now-somewhat-true-reset and you'll have a heavy pull so try not to short stroke this trigger" approach.

Fair enough, like I said, there's plenty of flavors. What you call the second reset on a DAK isn't a problem for me. On my DAK P226 isn't heavy at all, is very smooth and I can shoot it fast and accurate. Not so with striker fires, and they always feel like they're going to break when shooting fast. But whatever a fellow can use best is what he oughta carry, for sure.