I'm getting light strikes on my FS after about 4,000 rounds. Initially I thought it was due to the Apex FSS I had installed but the light strikes started before I had the kit installed so that can't be it. My gunsmith has installed quite a few kits and didn't think that was the issue but he did strip and clean the gun along with the slide, striker channel and spring. I was getting about 1 light strike every 150 to 200 rounds.

Today was the first time I had it to the range and out of 150 rounds I had 6 light strikes.

Like I mentioned, I have 4,000+ rounds through the gun and it seems to be getting worse so I thought I'd throw it out to all you wise sages of the M&P for your thoughts. I've been unable to find what the service life of the spring is. I'm tempted to just try a new Wolf spring since they're pretty cheap.

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NRA, ISRA, SAF, GOA, GSL

Did you try a new striker spring?

Sent from my SM-G955U using Tapatalk

I had a similar light strike problem with my M&P 40c. S&W sent me a new striker assembly (free), but that did not solve the problem. They then rebuilt my 40c, replacing the entire trigger mechanism, including the sear (all free), but that did not solve the problem. Finally, they sent me a new recoil spring assembly (free), and that solved the problem. My recoil spring assembly had about 4000 rounds on it at the time, so maybe it's time to replace yours.

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What, me worry?

Recoil Spring? I would have bet striker spring...

Interesting...

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NRA, ISRA, SAF, GOA, GSL

A weakened recoil spring might not return the slide all the way into battery. The resulting gap between the breech and the breech face may be hard to see, but large enough to prevent the firing pin from making good contact with the primer.

In my case, the recoil spring that failed with 4000 rounds on it was my second one. I had swapped out the original recoil spring assembly as a precaution at 6000 rounds, even though it was functioning perfectly. While I was waiting for the new (third) recoil spring to arrive from S&W, I reinstalled the original, and I experienced no further light strikes with it in 200 rounds. Apparently there is a fair amount of variation in how long these springs last.

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What, me worry?

Yeah, I'm with you on this one. I cannot see how the recoil spring will cause a light strike.

If an M&P is in battery enough to allow the striker to be released, then it's close enough to not cause a light strike. Because the rim of the case goes under the extractor, the round cannot be any further than that and still allow the gun to close enough to fire.



The striker spring makes the most sense. It could also be a worn striker. I have seen firing pins that have worn to the point of being too short.

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Freedom isn't free.

I went thru this a while back. Start with a new factory recoil spring. Before installing measure+record its length and compare it to the old one. Mine collapsed probably 3/4" after about 5k. The new one will take a little bit of a set after a few hundred rounds and then should hold for at least another 4-5k.
C.G.B.

Check and clean/replace the firing pin channel. A friend of mine is an armorer with the State Patrol, and they had a big mess with that issue in their issued M&P .40s. There was crud in it of some kind from wear, the nature of which I no longer recall. It created the same symptoms. I think they had to remove and replace the firing pin channel on all of their pistols.

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NHI, 10-8.

What ammo / primers are you using ?
If it's not ammo related speedshooterspecialties.com has m&p springs
on the cheap.

My original thought too but the slide was totally stripped and cleaned including the firing pin channel while it was at my gunsmith about a month ago.

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NRA, ISRA, SAF, GOA, GSL

I shoot mainly Freedom Munitions 124Gr RN both New and Reman. Thousands of rounds with never a problem until recently.

This time I was going through some Freedom 124Gr NATO which has also been 100% until now.

I'm dropping it off at my Smith this afternoon for him to do a deep dive. I'm going to go ahead and order a new Wolff striker spring just for giggles. They're cheap so no big loss if that's not it, and I'll have an extra just in case.

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NRA, ISRA, SAF, GOA, GSL

Not true. Put an empty case in the mag, release the slide stop and ride the slide closed very slowly while pulling the trigger. At some point just before closing completely, the striker will release and you'll see a light off centered strike on the primer.

This can happen with oversized bullets that don't allow the slide to fully close 1% of the time, a gunked up extractor claw that drags the cartridge face with resistance across the back of the slide or a combination that includes a weak/worn recoil spring.


The big culprit for me was shooting fat unsized powder coated bullets that were getting hung up in the narrow throat of my M&P40. Since then I have been sizing the bullets and seating the TC bullets to where the cone meets the rim.

I removed the extractor once and it was filled with congealed powder/cleaner and looked like granules of stick powder and I had also cleared the extractor claw of soot. I did get a new recoil spring from S&W being that it was over 3 years old and had about 30k rounds through it but in fact the new spring has 30k rounds through it and it still works just fine.

If you get another light strike, take the cartridge out and look to see if the strike is off center. If it is, the slide is not fully closing. You can't tell after pulling the trigger because the force of the striker tends to shut the slide the rest of the way.

My gunsmith seems to think it's the trigger bar. He checked and tested the striker spring and doesn't think there's anything wrong with it. He suggested replacing the trigger bar and $14 it's an inexpensive option.

He did show me that the slide can be just a tad out of battery and the striker will fire and cause a light strike. He actually demonstrated it.

We'll see what happens when I get it back.

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NRA, ISRA, SAF, GOA, GSL

This is a misnomer.

Yes, the slide can be back a tiny bit and the gun still fire. However, it cannot cause a light strike. The extractor will still hold the case against the breech face. If the case is against the breech face and centered over the firing pin hole, the gun will fire like normal.

This is the beauty of the tilting barrel mechanism. When the gun is out of battery, the primer is no longer in front of the striker. Thus a clean, working gun can't fire out of battery.

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Freedom isn't free.

Ah! Good point! I didn't think of that. But it does bring another question to mind. If the extractor isn't as tight as it should be, would this make a difference?

I haven't heard from my gunsmith so I'll need to ping him today.

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NRA, ISRA, SAF, GOA, GSL

Take the striker safety plunger out too...if it has one.
Brass shavings & gunk can get in there and slow things up.

That was all checked when I first took it in to the gunsmith. He did a complete strip down and cleaning.

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NRA, ISRA, SAF, GOA, GSL

I pick the pistol up at the gunsmith tomorrow. Happily, the range is right on the way so I'll be heading there right after I pick it up.

Keeping fingers crossed! If I get 250 rounds through with no issues, I think I'll call it fixed.

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NRA, ISRA, SAF, GOA, GSL

Well, much better. The striker block had a small nick that was catching the striker. He smoothed it out and I ran 250 round through with no issues.

Not calling it fixed quite yet but getting there!

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NRA, ISRA, SAF, GOA, GSL

I'm glad you seem to have it worked out. Did the smith show you where the damage was?

This is a S&W M&P striker block:


The only place where it could have had a "nick" that would catch the striker is the middle part. That's where the striker rides. If it was nicked, it was likely damaged and may not have been tempered properly in the manufacturing process. It would be worth the effort to replace it.

It's a $3 part: M&P Striker Plunger [1772] - $3.00 : Welcome to Speed Shooter Specialties

The Apex upgraded part is $35: Apex Ultimate Striker Block Not really necessary in my opinion.

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Freedom isn't free.

He took pictures of the block and is supposed to send them to me. This is an Apex striker block that was installed when I had the polymer trigger and FS sear installed. The light strikes started prior to that though.

As soon as I get the pictures I'll attached them.

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NRA, ISRA, SAF, GOA, GSL

If the light strikes started prior to the Apex install, how can the nick on the Apex striker block have been the problem?

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Freedom isn't free.

Exactly what I was thinking.

Not saying it's *the* problem, but a symptom. If I can find the original striker block in my box of original parts I'm sure I'll see nicks on that as well.

Here's the Apex striker block before he cleaned it up.

Attached Images

IMG_0184.jpg (99.9 KB, 27 views)

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NRA, ISRA, SAF, GOA, GSL

Comparing the two safety plungers, it would appear that the Apex might not have been lifting all the way clear before striker release. Or, possibly a manufacturing defect.

FWIW, the recoil spring assembly, trigger spring & striker assembly are supposed to be changed at 5K rounds.

I was looking for that information. Where did you find it?

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NRA, ISRA, SAF, GOA, GSL

From our lead armorer, the M&P was our issue pistol. Now, I expect I've gone beyond that personally with no issues, but you do regular maintenance to prevent issues. The extractors seem to live forever.

IIRC, Todd Green went well beyond that figure when he was doing his 100K+ round test of the early M&P. That was many years ago, not sure if his thread is still available on the M&P pistol website. (***************-I think). The tr spring seems to need replacement on a reasonable basis, but it's not as fragile as the same part in that Austrian thing.

Thanks for the info. I've put 500 rounds through since I got it back and so far no light strikes except for one NATO round. I'm calling that one a fluke. From what I've read NATO rounds can have hard primers and I don't normally shoot NATO anyway. I just happened to have a few boxes laying around.

I may still buy a replacement striker spring anyway and keep it around just in case.

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NRA, ISRA, SAF, GOA, GSL

I just noted your last sentence or I'd have included this in the PM I sent. You can't-SFAIK-buy just the spring from S&W. If you're a certified S&W armorer, you can buy all the pieces of the striker assembly and a slew of other parts not released outside the system. The rest of us can just buy the whole assembly.

On the other hand, I expect Wolff has the striker springs. I kinda figure that, given the life expectancy, I'm not losing anything by replacing the whole assembly. The extra benefit is that I'm not screwing around with itty-bitty parts and I can change the assembly in the field/at the match.

Yep, Wolff is where I'll grab a new spring.

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NRA, ISRA, SAF, GOA, GSL

I’m a Glock armorer, but I would clean the striker channel, replace the firing pin and striker spring. If that doesn’t work then I’d replace the plunger and plunger spring. Then I would replace the recoil spring.