What is the dead trigger issue I see pertaining to with M&P pistols?
I have a new M&P 9 and was curious.

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The Old Fart

A "Dead Trigger" is when you have fired a round, the slide cycles, charging another round, an failing to reset the trigger. This was an issue that arouse with some M&P pistols. I happened more with Pro series pistols and pistols that had heavier aftermarket sears in them. This was cause by the older sear black and the smaller sear spring. Recoil caused the sear to "bounce" from the recoil pulses and fail to grab the striker/firing pin on its way back into battery. S&W solved the problem by using a larger sear spring and plunger in the newer sear blocks. I have a DWJXXX series M&P9 that has the larger setup and I also have the APEX DCAEK and RAM in mine. 2000 plus rounds without a single issue. I had an M&P 40 FS in 09 that did have the dead trigger issue. Upon picking up this M&P I ran it through the wringer to see if it would hold up. So far it has proven itself and it is my current duty weapon along side my Glock G19. If you have a newer M&P, I wouldn't loose any sleep over it. If you have an older one, you can purchase a newer sear block assembly from numerous suppliers, or send it back to S&W if you have an issue. Thier customer service is top notch and will fix it up for you. TXPO

Texaspoff,
When was your DWJxxx pistol built?

I believe it was in June, or July 2011. I will double check when I get home and check the case package. I am on duty right now. TXPO

A broken striker would also cause a dead trigger. If you have a silver striker you don't have to worry about it - the new redesigned (silver) strikers have eliminated the problem.

Here is a write up I did on it: remat457 firearms blog * Blog Archive * S&W M&P Broken Striker (from Dry Fire) Evaluation and Replacement
(with pics)

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NRA Certified Instructor

After double checking mine was manufactured in June 2011. The dead trigger issue is different from a broken striker/firing pin. They both produce the saem result, but with the dead trigger, if you pull the lisde back just a slight bit, it will reset the sear and trigger. A broken striker/firing pin will not rest with that test. TXPO

I edited my post, more specifically I meant that a broken striker could also result in a seemingly non-cocking pistol with a dead trigger since the OP didn't list specific symptoms.

Good quick way to distinguish the two problems!

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NRA Certified Instructor

Jerry:

After about October 2010, S&W started slipstreaming new sear blocks, with a larger plunger & spring. That should fix the dead trigger problem before it starts.

However, what you get, even now, is anybody's guess without actually popping the sear out of the block (do it in a plastic bag!) to see.

"Slipstreaming" means "ship what's handy"....

The sear can flop around a bit during recoil, and may not engage the striker. Dirt/crud/whatever under the sear could cause this regardless, but the larger spring & plunger ought to fix that.

S&W will replace the spring & plunger (or otherwise fix this) if you report the problem, and they can reproduce it.

Apex will do the same for about $30 for customers and about $20 more for non-customers. (The sear block can be shipped as "parts", so there's no firearms surcharges involved. You'll want to talk to them about the actual price at this time.)

Seems to me that the 40's are more prone to this than the 9's, but that's just an impression. My 40C did do that immediately after installing a DCAEK kit from Apex. My 9C and 40FS, with unmodified sear blocks, but with DCAEK kits, have been fine.

It is NOT recommended that you do this yourself, but you can now apparently get plungers & springs (can't think of the name of the source). IMHO, you probably should have a good mill and good cutters, as it's necessary to take a small divot out of the sear block. I suppose a drill press might work, though. (I still think letting Apex do it is the best situation unless you're a machinist and have the hardware.)

You can also now get sear block assemblies that include the updated version of the spring & plunger, although I'm not 100% sure the usual suspects (Brownells, Midway) are going to ship the newer ones, even if asked. Last I heard (it's been a while), they were still shipping the old ones.

Still, at $30-ish, a new block, presuming you can return it if they ship the wrong one, is a very simple fix.

It also appears that while a DCAEK (or similar) mod will sort of force this problem in some cases, time and lack of cleaning under the sear (not easy) may also muck up a gun that's initially been OK. I'm going to do the other two MP&'s here when I get some extra cash.

IAC, while I'd be hesitant to carry a 40 with the DCAEK kit and an older sear block, you can generally shoot the heck out of it safely, although if you're competing in stuff that whacks you for failures, it might be a good idea to explore the fix.

Just IMHO, a DCAEK kit, sear block upgrade, and RAM kit (really best to install all of this at the same time - find out if you need the block upgrade while you've initially got it apart before shipping it) comes to a bit under $150, and, IMHO, is worth twice that.

There's another outfit out there - something "specialties" - that I can't remember right now that should have all the necessary parts for a DIY sear block update.

Swapping these parts (for the DCAEK kit) is a little complicated, but if you're a 1911 guy, pretty simple stuff .... Otherwise, it's not all that bad. 'Bout a half-hour of gunsmith bench time otherwise. Maybe $40 for the whole mess.

Regards,

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Stu.

Did this condition affect both full size and compacts in all calibers ?

John Law:

Can't speak for the .45, but I've seen comments on all of the 9mm/.357/.40 versions..... (Essentially the same sear block in all of those.)

IMHO, the .40 may be part of the problem - a little on the snappy side.

Regards,

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Stu.