M&P dead trigger

[Rastoff]

I agree with those that say the trigger bar loop needs to be adjusted, but I'm not sure it's just bottoming out.

Can you take the slide off and video it from the top while pressing the trigger please? I'd like to see if the trigger bar loop is fully under the sear or if it's slipping off the side.


On the subject of losing faith in your gun, I understand where you're coming from. However, I would also add one thing. I won't carry a gun until I've put at least 500 rounds through it without a single malfunction. If it can't do that, I won't trust it for self-defense. Along with that, if I have a failure, and I fix it, and then the gun will shoot 500 rounds without a failure, I'll trust it again.

 

[cbr6864]

Update my buddy came over as he has several M&Ps and does a lot of custom gun work. We measured the trigger loop it was gapped at .008. We removed the safety and it was still doing the same thing. He brought over an Apex poly trigger and we installed it. We had to open the trigger loop up to .023 to get the sear to drop every time. He has installed several apex triggers and said at most he has to open them up to maybe .015-.017. There looks to be wear on trigger loop and sear contact point. We are guessing enough metal had worn away for the trigger bar to no longer drop the sear, which is the reason the trigger bar had to be opened up so much. Calling S&W Monday

 

[Rastoff]

At 500 or even 1,000 rounds there should be almost no wear on either the trigger bar or sear. Something is definitely wrong with that trigger bar or sear.

 

[thecatch8]

A dead trigger represents a total and complete failure of the gun. It's a carry gun it needs to function 100% of the time. A few FTFs every now and then is one thing as you can clear those but a dead trigger leaves you dead in the water.

I'm going to call them to see if they will send me a new trigger bar free of charge as I hate dealing with sending a gun in.

Hope this helps.....it's important to take the time to learn your weapon system. Too many people dismiss educating themselves on something that could ultimately be used to save their life.

https://www.youtube.com/watch?v=zMLv_JaoSkU

 

[cbr6864]

It has nothing to do with learning my firearm the gun was bought brand new bone stock. Ran great for 400 rounds then just today it started having a dead trigger. I honestly think that the trigger bar hoop/candy cane is a weak link. Any movement in it and your trigger is dead.

 

[PastureOfMuppets]

10 will get you twenty it's down to the safety job and a garage gunsmith error.

This kind of failure tends to be paired with that... the odds of it not being are sky high.

 

[randyr5]

10 will get you twenty it's down to the safety job and a garage gunsmith error.

This kind of failure tends to be paired with that... the odds of it not being are sky high.

Yes. Seeing that safety lever move when he pulled the trigger was bothersome.

 

[cbr6864]

10 will get you twenty it's down to the safety job and a garage gunsmith error.

This kind of failure tends to be paired with that... the odds of it not being are sky high.

There was no safety job.....again the internals are 100% stock! Again the gun functioned perfect for several hundred rounds after the safety was installed. I found the problem will post video once it's done uploading. The problem appears to be the actual sear. As the sear block was made to be removable it is not held tight in the frame because only one roll pin in the back holds it together. The front of the sear would tilt up and down causing wear on the internals and finally a dead trigger.

 

[HeavyDuty Ken]

There was no safety job.....again the internals are 100% stock! Again the gun functioned perfect for several hundred rounds after the safety was installed. I found the problem will post video once it's done uploading. The problem appears to be the actual sear. As the sear block was made to be removable it is not held tight in the frame because only one roll pin in the back holds it together. The front of the sear would tilt up and down causing wear on the internals and finally a dead trigger.

From reading your posts it's unclear - was this a thumb safety equipped gun from the factory, or did you convert it?

 

[cbr6864]

The gun came with no safety I installed it a week after I bought the gun last year. My sear will tilt with or without the safety as I'm sure most will as well. The safety lever allowed you to tilt the sear with thumb pressure. Unless you have a good deal of over travel you will get a dead trigger then either by lifting the slide or pressing down on the safety you can release the striker.

As to why the sear was made to be removable as a separate piece I don't know. The front of the sear sits in the molded slots of the frame which allows movement in the sear


http://youtu.be/IRi-qA1ZmIE

 

[Fastbolt]

Call S&W and have the gun returned for examination.

When you removed the sear housing block to install a thumb safety, hopefully you didn't improperly align SHB when reassembling the frame, damaging the frame.

There have been some changes and revisions to the SHB's over time, as well as to the frame where they fit.

Also, it's possible to miss-align the trigger bar tail into the SHB if someone is inattentive or unfamiliar with proper assembly.

I'd not get involved in bending the trigger loop on the trigger bar, myself, even as an armorer who has been through the M&P pistol armorer class a few times.

There have been changes to the trigger loop over time, for both trigger pull weight compliance issues and for the new 'enhancements'. For example, the 'S' trigger bar loop has a 32 degree angle, while the 'H' loop has a 40 degree angle, and both angles are that way for a reason, in different models (with the 'H' trigger being part of the newer enhancements, and which can change engagement with the sear).

Let the company examine the gun and correct or repair whatever may have happened.

 

[cbr6864]

Don't see how the SBH could be assembled improperly as it is groves to sit exactly one way. I plan on putting the gun back the way it came new. Maybe I have the wrong frame which allowed the sear block to not sit tight in the gun but I doubt it as it came with plugs. Curious if any else with the new sear block sees that same amount of movement in the front.

 

[Fastbolt]

It's supposed to fit one way, but it's possible to let the front grooves slip out of place when looking at the rear. No force should be required to slip the SHB back in place, and pushing steel rails into plastic grooves isn't something to be forced.

Also, mixing older and newer production SHB's and frames can result in mismatched components due to some molding changes that have occurred, both with the ejectors and the front grooves.

They've also changed the length of the 2 pins in the SHB, and it's sometimes easier than you might think to let one or the other slip out of place a bit and get forced against, and into, the plastic frame during installation of the SHB. Mistakes made by production cell folks, technicians, armorers or smiths ... or kitchen-table tinkerers ... aren't the fault of the gun.

Installing the thumb safety lever assembly can also result in a misalignment of the SHB if you're distracted while positioning the safety so the coil pin can be installed.

FWIW, the thumb safety blocks rearward movement of the trigger bar (on the right side) when in the On-Safe position. It doesn't directly interact with the sear.

The design of the SHB and components aren't inherently 'fragile', but it's certainly possible for someone not trained and experienced in working with them to miss something that's become out-of-place or improperly positioned during disassembly & reassembly. Armorer classes can certainly have students easily and quickly make mistakes without realizing it, and that's after some procedure has been discussed in the class, demonstrated by the instructor and with the armorer manual (and their notes) open in front of them.

Of course, it's also possible for an occasional gun to exhibit some unrecognized problem with a part or assembly once it's been shipped and used for a while. That can happen with anybody's gun.

Let the company examine and address whatever's wrong.

If the "problem" doesn't occur after you've "put the gun back the way it came new", before you modified it, though, that might be a hint.

I'd still let the company examine it to make sure nothing's been damaged, or has become out-of-spec (for whatever reason), to make sure you have a safe firearm.

If you want them to install the manual safety for you, ask them to do it in the letter that accompanies the gun when it's returned.

Just my thoughts.

 

[cbr6864]

I know how the safety works but as you can see in the video the thumb safety lifts the entire sear block as it's only pinned in the back. I don't see how anyone could assembly the sear incorrectly it only goes together one way with one single pin holding it, it's not exactly rocket science. The design just seems flawed as the front floats. Even the sear block in my SD40 seats much tighter. I have had fit several components in my 1911s many times over the years this wasn't my first time doing something as simple as installing a safety.

There are several things about the design that don't make sense like the striker block. Unlike most it won't block the striker at rest only if the striker is fully retracted. Again I'm betting if anyone takes their slide off they can move the front of the sear. Put your finger in through the top of frame and against sear then lift up. The sear in any firearm should be rock solid with no play

 

[marine6680]

I have no movement in the block of my M&P.

When I did my Apex install, I had to close the gap on my bar to actually touch, no gap. I have no wear on my bar, and I had put near 1000 rounds on the factory parts.

Seems there was a problem with your pistol from the factory or after the safety install.

 

[randyr5]

I have a 9c made in early 2011, so it has the older sear block, but it is solid. It does not have any play in it, and I have had it in and out of the gun several times.

 

[cbr6864]

Found a few threads that mention the SBH floating around here is one

http://***************/mp-full-size-pistols/31671-m-p-45-fs-thumb-safety-loose-rear-frame-rails.html

Well I guess you can't link to another forum if you google m&p sear block loose it is first one. I copied a few post from the thread.



The response from the M&P Tech states

"I have checked with a pistol expert in Customer Service and we checked an M&P .45 pistol and the block did have the same amount of movement as yours, approximately 1.5mm. We believe the pistol is fine without any need for further repair."



Stopped by my lgs today. Looked at a couple m&ps of various sizes and calibers. Movement was various between all of them. However, an m&p armorer there said the movement is normal, some may have more than others. Even said it is normal to see the safety rise slightly As the trigger is pulled.


It looks like it is normal and varies from gun to gun....guess I got lucky and bought one that was on the loose side. I still say the SBH should be rock solid with zero play. Especial on a firearm like the M&P which for all intensive purposes is a SA handgun or at least 97% SA

 

[Fastbolt]

I didn't mean assemble the sear incorrectly, I meant install the SHB into the frame incorrectly.

I just went and compared some .40 & .45 SHB's, and a couple of 45/40c pistols.

The SHB's that allow for installation of the thumb safety assembly have a different (shorter) length & dimension of the R/F SHB rail (and corresponding frame groove). This is required because of the way the thumb safety moves and functions on the right side, requiring more space in the frame behind the trigger bar.

They also have a raised portion on the L/F rail, which is part of the design that holds the different style of ejector. The older ejector on the older SHB simply rested against the left side of the SHB, between the frame and the SHB. The new style also uses a headed sear pin to help hold the ejector, versus the flat pin in the older style.

The older SHB's that won't accept the thumb safety have a taller, thicker rail at that R/F spot (and correspondingly more plastic in the frame, without room for a thumb safety behind the trigger bar).

FWIW, my '08 production 45, with the thumb safety, allows for a small amount of up/down shifting at the very front of the SHB. It's been that way since the beginning (as has at least one other M&P 45 with thumb safety I've checked). It will also allow for a slight 'rising' of the left side thumb safety when the trigger is fully pulled. It functions and fires normally, and probably has more than 5K rounds fired through it by this point.

My 40c ('10 production), which wasn't made to accept the thumb safety option, has the other style SHB with the taller R/F SHB rail and frame groove. No movement in the frame. This gun has seen a little fewer rounds fired, and also functions and fired normally.

Both of my guns have the older less distinct 'softer' reset, although my 40c does have what I suppose might be called a 'transitional' slide stop assembly. It has the added lower R/R corner angled inward on the right side, was was done prior to the newest 'enhanced' design with the thicker welded sides, so the right side can add even more pressure against the trigger bar to aid in leftward movement back under the sear nose. It has a less distinct click before actual reset, but a noticeable click at the actual reset point. (More so than my older 45.)

None of this helps you, though, except maybe to suggest that whatever is happening with your 40c, it may not be involved with the movement of the SHB & L/S thumb safety, nor may those things even be a "symptom" of what's going on with your trigger/sear reset. Dunno. Not there to look at the gun.

If it's a problem with the trigger bar loop (meaning the angle, especially if the angle or 'gap' has been 'adjusted' at some point), which isn't letting it reset under the new sear nose 'teardrop' (versus the original sear with the D-shaped nose which resets over the trigger bar loop), and/or something else, it needs to be diagnosed and corrected.

 

[cbr6864]

I'm getting 23/1000" or .58mm of play in the front of my SBH if that was an actual response from S&W and they consider 1.5mm to within spec I'm sure they will say mine is within spec. Going to call them in morning

 

[Rastoff]

This is a very interesting thread.

I have a .45 full size with a thumb safety. With the slide removed, I can see a little movement of the sear housing block. However, that movement is really small. It seems to be less than the OP's.

I also have installed the Apex FSS. I cannot duplicate the OP's dead trigger issue. Neither can I get the sear to drop by lifting on the slide. Since the Apex install I haven't had even the slightest issue with this gun and I've put over 2,000 rounds through it.

I'm curious to hear what S&W says about it. We will have to be patient though. Their response over the phone will simply be to tell you to send it in. It's also unlikely that you'll get any explanation as to what they did do fix it, but we can always hope.