Striker Fired, how does it work.

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PolarFBear

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Hello Forum. I have been somewhat active in firearms for about 20 years. But I have questions on "STRIKER FIRED" weapons. How do they work? I look at cut-away drawings and disassembly instructions but the subject of actual mechanics is never dealt with in any detail. I only own one striker fired weapon, a Glock 17. The Glock shoots OK; not like a good 1911 or a SA Ruger (or any other handgun that I have firing SA). Another question, off topic for this Forum but still of interest, is OPEN BOLT firing. Just as with the "Striker" method I can find no detail on why full automatics are "Open Bolt". Steer me to good references please.
 
Thank Walt. As you read, 20 years in firearms; and I didn't get a start until just before my 50th birthday. These new fangled computers things Google/Wiki are still new to me. Forgot to look there. I was looking for "print" materials. I am to young to feel THIS old!
 
And of course (as the excellent wiki article on 'open bolt' states) not ALL fully auto guns fire from an open bolt. 'Cause that would make this hobby just too easy to understand.

Good luck.
 
Simple version

A striker takes the place of both a hammer and a firing pin.

A striker moves forward under direct spring pressure.

In the case of "Glock" the striker is sort of "half-cocked" by the reciprocating motion of the slide. Pulling the trigger drags the striker the rest of the way back then releases it.
 
Glocks and S&W M&P's have the firing pin partially (actually mostly) cocked. Pulling the trigger completes the cocking process then releases the firing pin. Technically they are double action only.

This is important to law enforcement agencies since most do not permit single action weapons. In fact many politicians and police chiefs were moving toward requiring DAO pistols for LE agencies when Glocks came out. Many cops decided that if it had to be DAO, then Glock was the best choice. This was a big reason why they became so popular so fast. S&W wanted a piece of the pie and made sure their M&P could be classified DAO

One of the reasons you don't see many Springfield XD's in LE is because they are fully cocked and pulling the trigger simply releases the firing pin. They are single action pistols. They actually work exactly like bolt action rifles which are also striker fired.

In know it is splitting hairs since in practice all 3 function almost exactly alike. But by definition the Glock and Smith are DAO. Once you learn how to use the trigger your Glock is just as accurate as most out of the box 1911's. It won't be in the same league as one with a target grade trigger or other modifications. Most try to use the trigger like a DA revolver. Take up the slack and you have a very crisp 5-6 lb trigger just like a typical 1911.
 
jmr said:
Glocks and S&W M&P's have the firing pin partially (actually mostly) cocked. Pulling the trigger completes the cocking process then releases the firing pin. Technically they are double action only. 40
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This is not meant to dispute your comments above, but to further clarify (or confuse) some points for the OP, who is unfamiliar with the terms.

The tradition definition of a double-action gun's trigger was that the trigger both charged the hammer or striker spring and released it.

The Glock and many other striker-fired guns partially charge the striker-spring, but the slide must do most of that function before the gun can be fired. (Some 3rd Gen. S&W hammer-fired semi-autos worked the same way: no second striker capability if you had a bad round. The trigger would work ONLY if the striker or hammer spring is first also partially charged/compressed by slide action.

I've seen these action types -- now very common in most of the new striker-fired guns -- called MODIFIED DOUBLE ACTION. That seems more correct to me, but "Double Action" is the term used by the gun makers.

The Glocks and most new striker-fired guns (like the new FNS 9, the VP9, SIG P320, my M&P Pro, and even my lowly Ruger SR9) don't have a second-striker capability: the slide must be moved first. (Not all the way -- just a short distance!) Glock called their design the Glock "Safe Action."

That some gun makers call their actions "double-action, is -- by the original definintion -- is rguably a minor falsehood, but its probably "marketing language" intended to make a more-complex idea more palatable and familiar to potential buyers.

There are striker-fired guns that are true double-action only weapons (using the traditional definition). The S&W 99 and some versions of the Walther 99, were considered SA, but when the decocker (which relaxed the striker spring) was used, they became true DA guns. You might call those guns SA/DA, like the hammer-fired (safety-equipped CZs). The CZ-100 was a true DAO gun.
 
I would argue that the M&P is not actually DAO... Unless you count moving the striker back about half a mm double action.

A trigger job or a drop in sear from Apex removes that little bit of movement from the equation...

I basically consider the M&P to be a SA, with a very positive sear engagement.


But as others have said, striker pistols differentiate themselves from hammer fired, by the fact that the firing pin is self propelled, and it gets its power by direct spring pressure,not a physical blow from another object.
 
Walt Sherrill

The Glock and many other striker-fired guns partially charge the striker-spring, but the slide must do most of that function before the gun can be fired.

The trigger would work ONLY if the striker or hammer spring is first also partially charged/compressed by slide action

I've seen these action types -- now very common in most of the new striker-fired guns -- called MODIFIED DOUBLE ACTION. That seems more correct to me, but "Double Action" is the term used by the gun makers.
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jmr40

Glocks and S&W M&P's have the firing pin partially (actually mostly) cocked. Pulling the trigger completes the cocking process then releases the firing pin. Technically they are double action only.
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There needs to be a simple widely recognized term for the partly recocking action. I suppose it is technically still DA because the trigger still does two actions. maybe 1.5 action.
 
For a striker, imagine a hammer that moves back and forth linearly instead of pivoting.

A striker fired pistol can be single action, double action, or somewhere in between like a Glock.

Glocks, Kahrs, and such are generally referred to as having pretensioned strikers. Imagine if you could fire a DA pistol from a half-cocked position. You get the benefits of relatively safe carry with a shorter lighter pull than a pure DAO would provide.

Wikipedia's entry on open bolt firearms is a little short, but explains the basic idea. Did you have any particular questions?

https://en.wikipedia.org/wiki/Open_bolt
 
marine6680 said:
But as others have said, striker pistols differentiate themselves from hammer fired, by the fact that the firing pin is self propelled, and it gets its power by direct spring pressure,not a physical blow from another object.
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It's increasingly complicated -- and our old definitions just don't work well, any more. And the complications are NOT limited to striker-fired pistols alone. That's why someone coined the term "modified double action."

The hammer in a hammer-fired gun doesn't do it's job by itself: it is powered by the hammer spring. With SA guns, 1) the trigger releases the hammer (as is the case with my BHP) but the hammer spring is either charged by the slide, or by thumb cocking; with others 2) slide movement partially charges the hammer spring, while the trigger completes the process and releases the striker, as is the case with some of the 3rd GEN S&W (DA) Semi-autos (and others?), and 3) there are true DAO guns that the trigger both charges the spring and releases the hammer in a single process.

The weapons in 2) above, called "double action," aren't able to do a restrike (without moving the slide). In the strictest sense of the term, they aren't "double-action." As someone earlier suggested, they're sort of 1.5 double-action.

Those three action methods roughly parallel what you see in striker-fired guns.
 
Partially tensioned striker... That what I call glock and similar pistols.

I do not use that term on M&Ps, XDs, PPQ, 320, VP9, and well quite a few other striker pistols.
 
marine6680 said:
Partially tensioned striker... That what I call glock and similar pistols.

I do not use that term on M&Ps, XDs, PPQ, 320, VP9, and well quite a few other striker pistols.
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Which of these guns have a second-strike capability? (I have an M&P Pro and an XDm and an FNS-40), but haven't seen, held, or shot a PPQ, P320, or VP9... Do you consider any of these other weapons Double-Action?

Or are they something different?

And how does this differ from S&W's 3rd Gen hammer-fired guns that also did not have a second strike (i.e., the trigger alone doesn't do it all) capability? I think the Kel-Tec PF-9 I owned fell into that same category.
 
I don't consider them Da at all, I consider them SA. They are fully tensioned.

So none of them have second strike.


As far as hammer fired pistols like you mentioned, those are partially tensioned/cocked hammers.
 
I just noticed your other post Walt...

There are definitely differences in the details, on what a striker fired action is, but I think you are overly complicating things.

A striker fired action, at its most basic, is just a firing pin the is driven directly by a spring. It does not require an impact from a separate part to be propelled into the primer.

How the striker spring reaches its compressive state is of little matter.

Completely tensioned
Partially tensioned
True untensioned DAO

In the end, a striker/firing pin, is propelled into a primer by a spring.


A hammer fired action has the energy of the spring that is eventually transfered through the action into the primer... First acts upon another part that is not the firing pin. The spring provides power to a part, which then impacts the firing pin, forcing it into the primer.

How the spring is tensioned is not important to define if it is a hammer fired action.

"But what of old revolvers?"

Well, they were the original "hammer" guns, so they slide.

"what about the Vz58?"

I consider that a "linear hammer" and not an actual striker.

The term has definitely evolved... It was probably originally meant to differentiate between firearms with an action that rotated a part about an axis as the main force to ignite a primer... From those that used a straight line vector for the forces involved.
 
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I would argue that the M&P is not actually DAO... Unless you count moving the striker back about half a mm double action.
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I have seen people insist that the XD has a partially preloaded striker like the Glock's, based on the tiny bit the striker cocked indicator is cammed back by the sear pivoting on it's pin.

:rolleyes:

And of course, this being the Internetz, there's no convincing them otherwise.
 
Just as with the "Striker" method I can find no detail on why full automatics are "Open Bolt".
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Some full-autos are open bolt; some fire from a closed bolt. Open bolt full-autos are fairly simple mechanically and tend to permit the gun to run cooler. There are several differences between a typical full-auto bolt and a semi-auto bolt. The firing pin in a full auto bolt is typically fixed and many full-auto bolts have a lip on he bottom of the breach face to feed the cartridge and make sure it is in battery before the bolt's fixed firing pin slams into the primer. Closed bolt versions of full-auto open-bolt guns (think UZI) have a different firing system, no fixed firing pin and the bolt-lip is missing so that they cannot be easily converted to full-auto.

Semi-auto open-bolt guns were essentially banned from production (I say this for simplicity - I know they weren't actually banned) in the early '80's because ATF considered them too easy to convert. Anyone who has actually owned a semi-auto open bolt would know that they really were not that easy to reliably convert to select-fire without mangling the gun. In other words, manufacturers of open bolt guns did attempt to safeguard against illegal conversion. The real problem was that open-bolt M10's, Demro-Tac's, and Tech-9's were very cheap, so criminals didn't care much about mangling their $150 M10.

So, take heed! If full-auto can be done easily and cheaply, IT WILL BE BANNED!!! Ref Akins device. Will really good bumpfire stocks be banned??? Never??? Really???
 
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marine6680 said:
A hammer fired action has the energy of the spring that is eventually transfered through the action into the primer... First acts upon another part that is not the firing pin. The spring provides power to a part, which then impacts the firing pin, forcing it into the primer.

How the spring is tensioned is not important to define if it is a hammer fired action.
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They terms you using are valid descriptions of how particular weapons tension the springs powering the striker or hammer (be they a Luger or Glock, or a semi-auto such as a S&W 3rd Gen or Kel-Tec Semi-auto). But that process has little to do with the standard definitions of single or double or DA/SA weapons. The standard definitions have always addressed the function of the trigger and not springs powering the hammer or striker.

You could argue that the traditional definitions are no longer valid, and I'd agree. That's why some folks are now calling the Glock-like actions Modified Double Action -- but that term is not widely accepted.

The following (inserted below) is from Wikipedia (although you'll find similar explanations and descriptions elsewhere and there is no mention of how the springs are charged or tensioned. The fulll topic is here: https://en.wikipedia.org/wiki/Trigger_%28firearms%29 The "action" descriptions address the action performed by the trigger.[/U] The underlining and bolding below are mine.

Single-action

A single-action (SA) trigger performs the single action of releasing the hammer or striker to discharge the firearm each time the trigger is pulled. [/U] Almost all rifles and shotguns use this type of trigger. Single-action revolvers such as the Colt Dragoon Revolver require the hammer to be cocked by hand every time the weapon is fired. Single-action semi-automatic pistols, such as the M1911, Springfield Armory XD and the Browning Hi-Power, require that the hammer or striker be cocked before the first round can be fired, although most designs cock the hammer or striker as part of the loading process (e.g., the act of inserting the magazine and operating the slide mechanism to chamber the first round also cocks the hammer or striker into the ready-to-fire position). Once the first round is fired, the automatic movement (recoil) of the slide cocks the hammer or striker for each subsequent shot. The pistol, once cocked, can be fired by pulling the trigger once for each shot until the magazine is empty.

Double-action only

A double-action, also known as double-action only (DAO) to prevent confusion with DA/SA designs, is similar to a DA revolver trigger mechanism. The trigger both cocks and releases the hammer or striker. However, there is no single-action function. A good example of this action is the SIG Sauer DAK trigger, or the DAO action of the Sig P250. For semi-automatic pistols with a traditional hammer (that employ only the double-action function of the trigger), the hammer will return to its decocked position after each shot. Subsequent shots require the double-action trigger firing sequence. For striker-fired pistols such as the Taurus 24/7, the striker will remain in the rest position through the entire reloading cycle. This term applies mostly to semi-automatic handguns; however, the term can also apply to some revolvers such as the Smith & Wesson Centennial, the Type 26 Revolver, and the Enfield No. 2 Mk I revolvers, in which there is no external hammer spur.​

In both descriptions, the "action" addressed is the TRIGGER's action. The Glock, M&P and other similar striker-fired guns, if you use the definitions above, aren't truly single-action nor double-action, but a hybrid of both. If you dry-fire a Glock, you can only pull that trigger once until the slide is moved a bit. That's not a double-action trigger.

Some striker-fired guns are single action, some are double-action only, and a few or that new, not-properly-defined hybrid.

I'd argue that most of the striker-fired guns are functionally much closer to being SINGLE ACTION weapons than DOUBLE ACTION (if only because they cannot and do not act as true DAO weapons), but SA seems to be a scary term for some folks, and the gun maker want to sell guns using terms that are less intimidating.

.
 
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