M&P gritty trigger fix

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kframefansc

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I did a lot of research on how to fix the gritty takeup on my new M&P9 and it seemed that the logical fix was to remove the striker block and polish the plunger and the bore hole. That is a PITA as it involves removing the rear sight. After spending nearly two hours of disassembly, fine sanding and polishing, and re-assembly, I didn't see any difference. The grittiness was still there. I had given the contact points on the trigger bar a lick and a promise but did not do a lot of sanding or polishing on it. After reading numerous posts here on the S&W Forum, I found that a lot of people actually got better results by simply polishing the trigger bar. I went back and did a more complete fine sanding and polishing of the trigger bar and voila, it was completely fixed.
 
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kframefansc said:
I did a lot of research on how to fix the gritty takeup on my new M&P9 and it seemed that the logical fix was to remove the striker block and polish the plunger and the bore hole. That is a PITA as it involves removing the rear sight. After spending nearly two hours of disassembly, fine sanding and polishing, and re-assembly, I didn't see any difference. The grittiness was still there. I had given the contact points on the trigger bar a lick and a promise but did not do a lot of sanding or polishing on it. After reading numerous posts here on the S&W Forum, I found that a lot of people actually got better results by simply polishing the trigger bar. I went back and did a more complete fine sanding and polishing of the trigger bar and voila, it was completely fixed.
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You don't happen to have pics of the parts of the trigger bar you polished, do you?
 
I polished the three sides of the pointed part that makes contact with the striker block. I used 2000 grit sandpaper wrapped around a popsicle stick and then polished with Mother's Mag with a small felt wheel on my Dremel. You can do this without removing the trigger. I just packed a rag all around the area I was polishing to catch the castoff from the polishing compound. I also blew it out good with compressed air after doing the work.
 

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I’ll bet your striker block polishing combined with the trigger bar have given you a smoother trigger than just polishing the bar.
 
CB3 said:
I’ll bet your striker block polishing combined with the trigger bar have given you a smoother trigger than just polishing the bar.
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I agree. I think both contact surfaces have to be glassy smooth to reduce the angular force on the SB plunger so that the resultant force on the plunger is mostly straight down. The plunger did have a slight raised edge which I knocked down by chucking the plunger in my drill and using fine stones from a knife sharpening kit to remove it. After removing the slight edge I then smoothed the entire surface, top and sides, with 2000 grit sandpaper and Mother's Mag polish.
 
Doing your own trigger job is a great project but if you really want the best trigger you can have on an M&P, Apex is the only way to go. The "25 cent trigger job" will make it better but it only takes you so far.
 
cmj8591 said:
Doing your own trigger job is a great project but if you really want the best trigger you can have on an M&P, Apex is the only way to go. The "25 cent trigger job" will make it better but it only takes you so far.
Click to expand...

I agree if you want to shoot competitively or are just OCD about having a great trigger. My gun is strictly for home defense and what I did to get rid of the gritty takeup and what S&W has done to improve the 2.0 trigger pull is all I need. Cost is a big factor and I don't see any benefit of adding $150 to the cost of a gun that is strictly used for home defense. When SHTF I don't think the Apex trigger will make any difference when the adrenalin is flowing.
 
kframefansc said:
I agree if you want to shoot competitively or are just OCD about having a great trigger. My gun is strictly for home defense and what I did to get rid of the gritty takeup and what S&W has done to improve the 2.0 trigger pull is all I need. Cost is a big factor and I don't see any benefit of adding $150 to the cost of a gun that is strictly used for home defense. When SHTF I don't think the Apex trigger will make any difference when the adrenalin is flowing.
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It's definitely a big investment that you need to justify and I think you are right about keeping the gun stock for a bed side gun. It will serve you just fine that way. I can tell you that if you decide to make the Apex investment, you don't have to worry about reliability issues. I run one on a M&P 45 and one on a Shield 45. Both of which are duty guns and have been shot thousands of times without issue. For me, the biggest fix was to go away from the two piece trigger, which I always found to be spongy. The Glock style, aluminum trigger just feels so much better for me. But if I had to stick to the factory set up, I would still carry those guns. Remember that practice will make up for any perceived shortcomings in your weapon system. Good luck!
 
Another point I would make on this issue is that the You Tube videos are a little misleading as to the cause of the gritty takeup. They have you push straight down on the striker block plunger to show that there is no gritty feel. They then have you push down at an angle and there is a gritty feel. Anytime you are pushing sideways on a metal to metal contact there will be a resistance regardless of how smooth the surfaces are. One guy even puts a small grinding wheel down in the bore. The point of this fix is that you want the trigger bar to slide over the top of the striker block plunger quickly and smoothly so that most of its force is directed straight down. That is why you polish the rounded top edge of the plunger and the contact points on the trigger bar. By smoothing out that initial angled contact the trigger bar moves more quickly and smoothly to the top of the plunger where it is pushing straight down with little or no resistance. Also, while polishing the top of the plunger certainly helps, I think the removal of that small lip with a fine stone was what created most of the improvement in the plunger surface.
 
I did the trigger job ala Mr. Burwell just the other day and IMO, the good reasons for DIY: I get to learn the inner workings of the M&P; I get to see the parts that are involved; the satisfaction of a job (well) done; Also, back in the day, right after the wheel was invented, when the only pistols out there were the revolver and the JMB 1911, the general consensus then was that when procuring a new pistol, a minimum 500 round "break-in" period was mandatory. Well, IMO, there HAD to be a better way, and there is - polishing all the internal parts (that's what all that shooting does anyway) (BTW, I have no problem shooting a bunch of rounds, but not for just breaking a gun in). Besides, it improves the performance of the pistol and the feel of the trigger and makes it more reliable.
However, to me, the plunger is only one part of the equation. The trigger bar works the plunger and the sear, so those need to be looked at as well. So as per instruction, I reshaped the cam on the sear (to a teardrop shape) and then polished it and then polished the side of the loop on the trigger bar and then the top of the loop and then polished the lug on the striker. So now it's really close to a JMB 1911 trigger. IN fact, can't hear or feel the reset (but I'm sure it does) BUT just to be sure I have RAM incoming for it.YMMV
 
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CCHG—minor detail: the trigger bar pushes up on the striker block, not down. As soon as the trigger bar contacts the SB, it starts moving up.

The speed that the trigger bar is moving is inconsequential.

Some beginning lateral force has to be translated to vertical movement. The polishing of the SB tunnel and the body of the SB contribute to a marginally lighter and smoother trigger by reducing metal-to-metal friction.
 
CB3 said:
CCHG—minor detail: the trigger bar pushes up on the striker block, not down.
Click to expand...
Yes, I realize that. I looked over my post and don't see where I said up or down. I said that the trigger bar works the plunger and it does.

CB3 said:
As soon as the trigger bar contacts the SB, it starts moving up.
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Hmm, the trigger bar moves up? That's what that sentence says...lol

CB3 said:
The speed that the trigger bar is moving is inconsequential.
Click to expand...
Umm,OK, and....Did someone say otherwise, or....

CB3 said:
Some beginning lateral force has to be translated to vertical movement.
Click to expand...
Wow, (I feel I'm in the twilight zone), so, something moving sideways has to translate into vertical movement. OK, well, I'm glad we got that cleared up.:eek:
 
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CCHGN—I apologize. I meant to refer to the post above yours by kframefansc. Sorry.
 
kframefansc said:
I polished the three sides of the pointed part that makes contact with the striker block. I used 2000 grit sandpaper wrapped around a popsicle stick and then polished with Mother's Mag with a small felt wheel on my Dremel. You can do this without removing the trigger. I just packed a rag all around the area I was polishing to catch the castoff from the polishing compound. I also blew it out good with compressed air after doing the work.
Click to expand...

I tried doing this. Polished the **** out of it. No difference. Still the same gritty movement.
 
My wife bought a m&p9c soon after they came out and like others have learned debuting of all edges ,a rounding of corners and polishing of the trigger bar can go a long way in smoothing up you trigger pull and make it lighter .

Adding the apex striker block will still leave you with the same stock trigger pull length but you might find your trigger pull is in the low 4lb range and smooth.
 
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