Eradicate the grittiness of your M&P trigger

[Arthury]

As many of you may already know, you can buy an Apex USB kit to replace the original Safety Plunger (SP) to achieve this.

What is causing the grittiness?

• If we look into what is causing the grittiness, we will realize that the flat surface of the SP that will be in contact with the trigger bar activator has small tiny concentric ring-like ribs on it. Those ribs are the ones that produce the grittiness. All you need to do is to polish those rings away.
• Next, if look carefully, you will see that the circular edge of this same top surface has a 90 degree abrupt drop to the cylindrical edge. You will need to polish the abruptness on the circular edge away so that the edges are not 90 degree but a smooth and more gradual curve drop to the cylindrical vertical edge. This way, when the trigger activator moves across the mirror surface to the edge, that smooth curve will give it a better glide.

In celebration of July 4th, I shall share with you how this can be done in less than 30mins.

Tools needed

1. A small table vice
2. Small hammer
3. Flat edge metal file used to knock the rear sight out
4. Automative boy work smoothening block
5. Automotive body work scratch remover (smallest grain)
6. a couple of pieces of cloth

Disclaimer/WARNING: This posting is for informational purpose only. If you attempt to do this, you may lose your S&W warranty and may incur risks that can cause serious injuries/death. Do it at your own risks.

Here's what I did to mine:

1. Remove the slide, like the way you do for a field striping/cleaning
2. Wrap your slide with a cloth before you clam it on your vice so that the vice will not mar the surface of your slide
3. Remove the SP per the Apex YouTube video to install their USB. Note that if this is your first time sliding off the rear sights, it may require several strokes of your hammer to even shift it 1/8", so wrap whatever you are using to hammer the rear sight with some kind of cloth so that you will not destroy the surface of your rear sight.
4. Remove the SP and polish that surface with an automotive body work polishing block. Be gentle with the polishing and check often to see that your are polishing only the rings away. You want to do this slow so that you are not taking too much off. The intention is to only remove the tiny concentric ring ribs without changing the size of the actual SP. In fact, if you feel uncomfortable about taking off too much, you can just take off enough so that the rings are barely there. That's good enough. You really do not need to completely rub off the rings.
5. After you remove the rings, polish it to a high shine using a fine granularity automotive scratch-remover (like Meguiar). This step will make you proud after you are done. I can see my face on its mirror-like shine.
6. Re-install the SP back following the reverse procedural steps

When you're done polishing that SP, it should have a mirror shine.

After I re-installed everything back, my trigger is now smooth and has lost that grittiness. Remember, you are only removing the grittiness. The trigger travel distance has not changed. If you want a gun for competition, you will still need to get the Apex competition hard sear and the shorter striker spring to lighten the trigger.

 

[bobkarno]

A file to knock your sight out? Yikes! I can't look.

 

[Arthury]

Obviously, if you have a sight-press, use one.

 

[D Rock]

Arthury, thanks for posting that!

I'm glad to see people doing their own smith work and problem solving. Over at the M&P Pistol Board a member named mp9werks used to post many well done pics for doing your own work like that.

I know Apex makes a fine product, but if you are mechanically minded you can do this work yourself.

I must have one of the only M&Ps that never had the grit problem. As a matter of fact bought in '08 and no problems since.

Thanks for sharing.

Dave

 

[Reader850]

I bought a FS 40 and a 9c last year. The 9c trigger was excellent. The 40 was poor until I installed the Apex kit, except for the part under the rear sight, which refuses to slide out!

 

[Arthury]

I share the same experience as yours. My first buy was the 9mm and the trigger is not smooth at all. But, my M&P45 is actually quite smooth.

 

[LouisianaJoe]

My M&P 45 is smooth enough for me. I never noticed any grittiness.

I probably will now. Sometimes ignorance is bliss.

 

[Zeke2839]

I am fairly new here. When I first started posting, just about every gritty trigger post I read said that the gritty feeling would eventually wear out after about 1000 rds or so. They read that the trigger only gets better with more rounds. Sounds like this piece that you are filing is what breaks in after time of use. Can anybody elaborate on this??

 

[Rangel]

Re:

>>>Tools needed
A small table vice
Small hammer
Flat edge metal file used to knock the rear sight out
Automative boy work smoothening block
Automotive body work scratch remover (smallest grain)
a couple of pieces of cloth

Disclaimer/WARNING: This posting is for informational purpose only. If you attempt to do this, you may lose your S&W warranty and may incur risks that can cause serious injuries/death. Do it at your own risks.<<<

PS--"Children, do not try this at home!"

 

[Arthury]

Confirmed on the range

First time at the range after the polishing confirmed that what I did was correctly done with 150 rounds of trial shots.

Trigger is now more predictable and smoother.

At 7 yrds, my accuracy has improved markedly (i.e. 30-40% improvement) and I can place the shots alot more predictably. I can safely say that above 80% of the shots were within 1/2" groupings.

I am expecting another quantum jump if I were to replace the sear with a competition Apex sear.

 

[Coaltminer]

My 9c was purchased in March of this year, fired casing indicates June of 2010. Never had the grittiness problem that some people have mentioned, but I'm glad there is a fix for this issue. However, after reading this, I'm happy that I didn't need to do this as I'm not that handy. Hammers and files are my go-to "gunsmith" tools!

 

[bobkarno]

The Apex sear offers an excellent reduction in travel between the break point of the sear and the trigger stop. This feature improved my accuracy notably. Its improved geometry will also lessen your pull weight into the 4lb range.

 

[mkygod]

The gritiness is just for a better feel right? Does it actually affect the way you shoot?

I would think that the actual trigger break is more important in that regard. Mine's definitely got the grit but its not something I notice at the range.

 

[D Rock]

I think if you don't notice it than no problem but ,if it distracts you, then it will certainly change the way you shoot and potentially your accuracy.

Dave

 

[Arthury]

The gritiness is just for a better feel right? Does it actually affect the way you shoot?

I would think that the actual trigger break is more important in that regard. Mine's definitely got the grit but its not something I notice at the range.

Removing the grit increases predictability at the micro level. Since it is smooth, your one smooth trigger pull is executed with no questions asked.

With the grit present, the micro control is occasionally interrupted and you may need to increase the trigger pull a tiny bit along the way to overcome the grit. This makes the trigger pull deviate from an ideal constant pressure pull. As you may already know, a non-constant trigger pull is one of the causes of inaccuracy.

Those are just my opinions. I am not a gunsmith nor do I have 30 years of tinkering with gun internals under my belt.

 

[AKsRule]

My 2 cents.

There's absolutely nothing wrong with polishing contact surfaces
between parts as long as you don't remove surface hardening or
use Power Tools.
.

 

[mkygod]

Removing the grit increases predictability at the micro level. Since it is smooth, your one smooth trigger pull is executed with no questions asked.

With the grit present, the micro control is occasionally interrupted and you may need to increase the trigger pull a tiny bit along the way to overcome the grit. This makes the trigger pull deviate from an ideal constant pressure pull. As you may already know, a non-constant trigger pull is one of the causes of inaccuracy.

Those are just my opinions. I am not a gunsmith nor do I have 30 years of tinkering with gun internals under my belt.

Yeah I can see now how that could affect your consistency. I think it differs from person to person.

 

[ET.]

I bought a M&P 40 Pro & the trigger had been tuned at the factory. Virtually no grittiness & the trigger is about 4 lbs. with a really tight reset. I love the feel of this trigger. Sure the reset isn't as pronounced as a Glock, but it doesn't take a whole lot of practice to learn where the reset is. You can definitely feel it if you are in tune with your gun. I harmonize rather well with mine, thank you...

 

[Arthury]

I bought a M&P 40 Pro & the trigger had been tuned at the factory. Virtually no grittiness & the trigger is about 4 lbs. with a really tight reset. I love the feel of this trigger. Sure the reset isn't as pronounced as a Glock, but it doesn't take a whole lot of practice to learn where the reset is. You can definitely feel it if you are in tune with your gun. I harmonize rather well with mine, thank you...

That's good to know. Someday, I may get a pro when my M&P's wear out.

 

[growr]

I tuned mine one round at a time. After 15,000 rounds it seems to run just fine. M&P FS .40 The money I could have spent with after market stuff went into more components. Has never missed a beat for me.

Randy