M&P.40 FTF

[NU9MM]

Ok bought a .M&P full size .40, took it to the range for my first range day with it. Slide was open inserted my first 15rd mag released the slide and the round jammed. Locked the slide open cleared it released the slide same thing. It happened again 3-4 more times. The RSO took a look and it did the same thing to him. Put the 40 away and finished out my day with my 9 mm. Went upstairs into the retail part of the store and talk to one of the armorers up there and another employee. They both took a look at it tried to get it around to feed it would not feed. One of the armorers took it down to the range he said I'll try a new mag in it. He said it could be a bad back mag. He came back up and said nope it's not feeding either. I did not think to take any pictures of it while I was down in the range. But it was like the rounders getting jammed like in these pictures I found. The Armorer advised me to call S&W. It appears to be a LE trade in there is a faded badge insignia on the slide. Thank you in advance.

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[Ben B.]

Does the extractor move if you press on the hook?

One thing that is helpful is to use slo mo video function on the the camera on your phone. This lets you get an idea of what is happening. Usually easier with a buddy doing the filming but can be done alone.

If you have dummy rounds, can video it at home. I suggest NOT trying to video record a malfunctioning pistol with live rounds at home.

 

[NU9MM]

Does the extractor move if you press on the hook?

One thing that is helpful is to use slo mo video function on the the camera on your phone. This lets you get an idea of what is happening. Usually easier with a buddy doing the filming but can be done alone.

If you have dummy rounds, can video it at home. I suggest NOT trying to video record a malfunctioning pistol with live rounds at home.

Thank you I for got to mention that the armorer cycled snap caps with no issues what so ever. Just field stripped the weapon the extractor is solid. I will try again tomorrow with on of the brand new never used mags and the other old mag to try and duplicate the failure again. I fella I bought it from said, the M&P's he's shoot have all been reliable. But couldn't speak about the one I bought from him, since he said he never shot it! I will take pictures of the failure and post it tomorrow if it happens again m.

 

[Saladfarmer]

As Ben just said, the extractor being bound up will cause exactly what you're talking about. If you press on the extractor (on the outside of the slide above the trigger, not the claw) with your finger, does it move at all? A dummy round will not properly diagnose an extractor problem as the plastic dummy round has more give and won't resist the force like brass will.
That being said, is the round not not going all the way into battery or getting pushed up and not into the chamber at all?
M&P's generally are not that ammo finicky, but I would also try different profile projectile rounds if possible, are they factory rounds you're using in it? another question or variable to throw in there...
Most likely the extractor, the spring or it just needs to be cleaned up and broke free from not being used in so long.

 

[NU9MM]

No the extractor does not move at all when pushing on it. I bought Sellier & Bellot 180g ammo at the range. But I also have CCI Blazer 180g that I didn't try.

 

[TTSX]

Not to be snarky, there's usually a reason someone is selling a gun and I think you found out why. The reason the last owner "never shot it" was because he couldn't, not because he didn't try. That sucks but it's fixable

 

[NU9MM]

Not to be snarky, there's usually a reason someone is selling a gun and I think you found out why. The reason the last owner "never shot it" was because he couldn't, not because he didn't try. That sucks but it's fixable

You're not being snarky just giving your honest opinion. I'm going to call S&W tomorrow. Hopefully I can get it fixed for little $$$

 

[NU9MM]

Well I tried the Blazer ammo same result. It just almost feels like there's not enough spring pressure on the recoil spring like it just doesn't have enough push to put the slide into battery. The one Armorer said he had to hit the back of the slide with his palm to get it to close. Here's a picture I took this morning.

 

[NU9MM]

I was able to get the round into battery by releasing the slide with the slide catch lever this time however, when I racked the slide to put the other round into battery it wouldn't feed it. When releasing slide it just did not feel like there was much force behind the slide going forward. Just trying to give as much info as I can.

 

[Ben B.]

I'd take the slide off the gun, take the extractor out and clean up extractor, spring, plunger and tunnel, and put back together before doing one more dern thing.

 

[NU9MM]

I'd take the slide off the gun, take the extractor out and clean up extractor, spring, plunger and tunnel, and put back together before doing one more dern thing.

Not real adept at breaking down my firearms beyond basic field stripping for cleaning. But I'm finding outs it's an important thing to know.

 

[Ben B.]

View: https://m.youtube.com/watch?v=BNmewunSEio

 

[NU9MM]

View: https://m.youtube.com/watch?v=BNmewunSEio

Not that this matters or maybe it does. The .40 I bought is a LE trade in. It has very weak tritium night sights and a badge insignia on the slide. I would think it was well maintained with it being a LE trade in. But then again maybe not.Or are these fatal flaws of the .40 cal due to the higher pressure rounds. Internals just wear out faster. Has soon as I get home I'm going to remove the extractor and spring in throughly clean them and the channel.

 

[Ben B.]

The tritium sights are faded because that is what happens with tritium. "Fatal flaws of .40 cal" is just fatalism. The SAAMI max chamber pressure of .40 is the same as 9mm, 35,000 PSI. The main issue for early .40 pistols and kabooms was thinning metal in 9mm guns to fit .40, poorly supported chambers as a consequence, and reportedly over thin brass. The M&P .40 was built around .40, not a retrofitted 9mm design.

I suggest you follow thru and examine the extractor. Hopefully that will be it.

 

[Saladfarmer]

Well I tried the Blazer ammo same result. It just almost feels like there's not enough spring pressure on the recoil spring like it just doesn't have enough push to put the slide into battery. The one Armorer said he had to hit the back of the slide with his palm to get it to close. Here's a picture I took this morning.

View attachment 1884154

extractor needs to be cleaned out and the channel where the screw is and/or replaced. pretty much guarantee it seeing the picture and hearing the story. Similar thing will happen on pistols with red dots that have had screws too long and are pushing against the extractor spring channel.

 

[Bill Siegle]

Could just be a weak recoil spring. I've had similar problems with used guns and a simple(and cheap) fix was replacing the recoil spring.

 

[NU9MM]

The tritium sights are faded because that is what happens with tritium. "Fatal flaws of .40 cal" is just fatalism. The SAAMI max chamber pressure of .40 is the same as 9mm, 35,000 PSI. The main issue for early .40 pistols and kabooms was thinning metal in 9mm guns to fit .40, poorly supported chambers as a consequence, and reportedly over thin brass. The M&P .40 was built around .40, not a retrofitted 9mm design.

I suggest you follow thru and examine the extractor. Hopefully that will be it.

Ok. I was just thinking out loud. And I've always heard that about the M&P platform that it was built around the 40 not the 9mm.

 

[NU9MM]

extractor needs to be cleaned out and the channel where the screw is and/or replaced. pretty much guarantee it seeing the picture and hearing the story. Similar thing will happen on pistols with red dots that have had screws too long and are pushing against the extractor spring channel.

Could you please highlight what you are talking about in the picture if you could. Thank you.

 

[Ben B.]

Could just be a weak recoil spring. I've had similar problems with used guns and a simple(and cheap) fix was replacing the recoil spring.

Agree, this is another possibility.

I would first remove/examine/clean out the extractor & spring & tunnel. This takes care of a no cost possibility, before buying things that may not fix problem. Though a spare recoil spring is always good to have on hand.

 

[Ben B.]

If the extractor is stuck/sticky it may not allow the rim to slip under and against the breech face, resulting in a nose high feed jam. But once the case is in there, that extractor is a tight mofo, and "extraction" from the chamber is no prob Bob. Sometimes (rarely) erratic ejection can be a problem if the extractor is holding the rim too tight when the ejector strikes the case head.

If you can lock slide back and work a case into position against the breech face, it'll probably chamber that round when you release slide. And extract it when fired.