S&W M&P Sear Housing Block - "Dead Trigger"

GeerGuy

GeerGuy

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I have an M&P 9 Pro that has been very reliable for the first ~1900 rounds, but tonight I had 3 "dead triggers" out of 100 rounds. I did some research and found that this is a known issue with the older M&P's, especially the Pros. S&W has a fix for it and all newer guns should come with it already. The new version of the sear housing block has a larger plunger and spring.

I need my gun for a course in ~2 weeks, so sending it back to S&W is out for now.

Does anyone know where I can get a new style sear housing block for a gun with no internal lock and no mag disconnect?

Thanks
 
Try Brownells, followed by Wortners, followed by Murray Charlton Enterprises. If that fails, ask Wortners or Murray if they can mod the block for you - it has to be milled to accept the larger spring and pin, it can't just be drilled because the larger spring bore is on a very slightly different centre. You could also try bumming a block from a standard (newer) M&P and running that. The block is an easy switch. If you come up dry let me know, mine has an Apex sear in it and has the mag safety intact, but I'll lend it to you if you're really stuck. Strangely mine is an older M&P but it's been flawless for 20 some odd thousand rounds.
 
Brownells only has the "Sear Housing Block Assembly, Standard" listed, this version has the mag disconnect and internal lock. I know that the mag disconnect can be removed, but I'm not sure if this will work in my gun, since I don't have the internal lock??

I will call the other places.

Thanks for the offer, if it comes down to that I might be able to borrow one from my brother.
 
brownels is the only place I have ever found in multiple years that stocks parts like that for my MP

question, when was the last time you disassembled the upper slide, and took out the striker and its assembly yourself to clean it?
 
[youtube]?v=B6nebJaORy0[/youtube]

thats how you get into the internals to check, maybe just some lube, fine cleaning is required.
 
It was field stripped and cleaned after every use. I just took apart and cleaned the striker and the sear housing block. Both were pretty clean, a little crud on the striker. I will test fire it on the weekend.

It looks like I can use the one from Brownells, both the mag disconnect and internal lock can be removed.
 
hope that fixes it, if you get in a bind, I do have a spare spring for the sear in edmonton here, but you would have to pick it up
 
I ordered the sear block from Brownells, but I refuse to give UPS any money, so it might not make it here in 2 weeks. My backup plan is to use my brothers receiver with my barrel and slide, so I'm covered.

All reports say that the updated sear block will fix the issue.

I will report back...

Thanks
 
What is happening is that the trigger bar (silver bar that runs from the trigger to the sear) has side to side slop.

Take the slide off the pistol.

with the pistol frame in your right hand look down at the top of the pistol frame. There is a void on the right hand side near where the trigger bar runs under the sear block.

Take a small piece of foam (high impact flooring foam works.... a piece from interlocking floor tiles) cut it to size so that it fits in the void. Your problem will dissapear.

This is not a permanent solution, but it will get you by for a bit until you can source replacement parts from smith. BTW the apex trigger kit will also solve this problem....

Mine has not had any issues but a fella at the club had this same issue with his pro. Oddly enough this is only a problem with the pro model. Standard M&Ps don't have the 'void'......

My buddy who did this mod ran 1500 rnds through his pro before the trigger parts arrived and the foam bit is in exactly the same shape it was when it went in.

Hope this helps,
Cheers!
 
Thanks for your comments.

It is a well known issue that can occur with both the Pro and non-Pro, and it has been addressed by S&W with a larger spring and plunger in a new sear housing block. The 'void' is the same for Pro and non-Pro, as the frame, sear block and trigger bar are the same. There are other differences with the Pro that might make it more susceptible to this issue.

I assume that you are talking about inserting some flexible/rubber type of material here, between the frame and the trigger bar:

MP_Sear.jpg


This would be a very last resort type of mod for me. I have ordered the replacement sear block and have a backup gun, but if I can reproduce the issue at the range this weekend, I will mess around with this mod a bit.

Thanks
 
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