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Discussion Starter #1
I was getting near the 300 round mark, without cleaning my M&P when it happened. I reloaded, pulled the trigger and it just went to the rear. Ahhh…I didn’t seat the magazine, I thought, but it was seated. I removed the magazine and reinserted it; still the trigger wasn’t connecting. I removed that mag and inserted an empty mag; still the trigger wasn’t connecting. I inserted a mag with 5 rounds in it, and racked the slide. The trigger connected and I didn’t see the problem again. Still if my life had been on the line, instead of on the range, I likely wouldn’t be writing this.



I wish now that I had tried to evaluate the problem at the range, but the lighting in the “booth” isn’t that great and I guess I wanted to see what it would take to get it going ASAP.



When I got home, I called S&W service and described the problem, and of course they had never seen or heard of such a thing. They suggested that I clean it and fire some more rounds through it and see how it does. If it did it again, he suggested that S&W would need to take a look at it.



I field stripped it and examined the mag disconnect. It worked perfectly and there were no signs of a problem.



I think this will prove to be a fluke. I believe something, dirt/debris, or perhaps a flake of flashing or something from the factory, got between the trigger bar and the frame, preventing the trigger bar from engaging the sear.



I doubt that I’ll ever know. However I have fired another 200 rounds through it without any hint of a problem and I still haven’t cleaned it. I’m gonna do 100 more rounds and then clean it good.
 

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I ran mine 300 before the first cleaning as well, my only real

form of torture test other than shoot the snot out of it for decades to come.



Piece of junk or dirt? Probably. I'd like to know what ammunition you were shooting.



I clean mine after every shooting session, and each session could be 50 rounds or 300 rounds. The trigger mechanism does get a bit dirty, but nothing three Q-tips and a few patches won't cure easily.



My trigger group has never given me issue for concern.
 

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I clean mine after every session as well. I usually fire around 300 rds, mostly from the Remington UMC ammo which leaves the gun very dirty.
 

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Discussion Starter #4
I was using Blazer AL case. I would normally clean a gun more frequently, but on a new gun I like to run about 500-600 rounds through it to see how it handles the build up.
 

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Man, if that was me I'd try hard to reproduce the problem... it sucks because its going to hang over you now. I for one hope it happens again, and again and again so S&W can locate it, fix it, and explain exactly what caused it.



Kinda puts a damper on things. A fluke failure to feed or failure to fire is one thing, but this is entirely another because its not something immediate action drills can cure.
 

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Discussion Starter #7
Well, that is one way to look at it. But I shoot 100 rounds a week or more so over the next six weeks, I could easily put 700-800 rounds through it. If there's an on going problem, it's gonna show up.



I've heard of similar problems that go away on their own. But I do agree that a problem that can't be solved quickly with an immediate action drill is serious.
 

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well, it wasn't something getting betweetn the trigger bar and the trigger bar and the frame. If you examine the disconnect mechanism, you will notice it pushes the trigger bar TOWARDS the frame to keep it from firing. Having something jammed between the bar and the frame would act to keep the trigger bar engaged rather than disengaging it.



Based on your description, what happened is that the striker did not engage the sear and become pre-cocked. You played with the mag twice, which will not change an uncocked gun into a cocked gun. then you actually racked the slide, which cocked the gun, and it went boom.



When you racked the slide after inserting the mag with 5 rounds in it, did a live round or spent case eject? If it didn't, an empty gun with a loaded mag in it not going click or boom isn't that mysterious. Some sort of user error occured. Brain farts happen.



The only way grit or grime could have cause what you are describing to happen, as described and assuming that you actually loaded the gun properly and a round came out when you laoded the 5 round mag, is if something wedged between the sear and sear block that kept the sear depressed/in the pulled position.



Frankly, I've had my M&P dirty enough that it looked like the crap built up on an engine leaking oil that someone had sprinkled gold glitter on in there, and everything still worked fine.



Brain farts can get you killed, but it's not a QA issue with the gun.
 

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Based on your description, what happened is that the striker did not engage the sear and become pre-cocked.


Brain farts can get you killed, but it's not a QA issue with the gun.


If the striker did not engage the sear (ie failed to catch as the slide came to the rear) wouldn't A: very much be a QA issue with the gun, B: of caused it to fire out of battery? or would the firing pin plunger of prevented that but not held the striker back enough to engage the sear?



I do see that if he simply loaded and unloaded magazines without racking the slide it would have failed to cure his incident, but we are not entirely sure this is what he did. Did you rack the slide when switching magazines Tangle?
 

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Discussion Starter #10
raz-0,



I'm not so sure. It is true that the trigger bar moves away from the frame to engage, but the possibility still exists that something interfered with the trigger bar engaging the sear.



It's been a while since this happened and a bullet did eject from the chamber, but I can't remember at what point I saw the bullet eject.



Typically what I was doing was firing five shots to slide lock. I then inserted another mag of five rounds, released the slide, and pulled the trigger. Once when I did this the trigger simply pulled all the way to the rear.



The first thing I did was tap the mag to make sure it was seated, it was. The next thing I'd normally do is rack the slide; that would pre-cock the gun. I don't remember specifically that I did that but that's what I would normally do. Then I inserted a different mag and would likely have racked the slide again, but again, it's now been too long to remember the details. I do remember at one point looking down into the gun. So we know that the slide had locked open on the last round which would have pre-cocked the gun, but the trigger pulled freely to the rear. The fact that I looked down into the gun indicates the gun would have been pre-cocked with the slide locked back. But when I inserted an empty mag at that point, the trigger did not engage the sear.



Going through the repeated sequence of shooting five rounds to slide lock, reloading, and dropping the slide for nearly 50 rounds (by the time the mal occurred), makes it extremely difficult to explain how the gun got uncocked during this procedure.



Yet, an uncocked gun would allow the trigger to pull all the way to the rear and feel very much like the trigger was disconnected. Also, it would make sense that inserting a mag, with 5 rounds in this case, and racking the slide would place the gun into the firing mode. But the question remains is how does one get from slide lock to uncocked when you just loaded a mag and dropped the slide? Even if a round didn't chamber, the gun would be pre-cocked.
 

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Hard primer?



You said you re-loaded, pulled the trigger and nothing happened... maybe the striker did fall but didnt touch off the round



it doesnt sound like it fires untill you racked the slide again later down the road



500 rounds without cleaning isnt going to hurt this thing



I ran 750 in about 4 hours without cleaning... the front of the pistol back to behind the 1913 had a nice matte black finish on it 8)
 

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Discussion Starter #12
FastSS,



It's not likely this was caused by a hard primer. The last round in the mag fired and locked the slide back. I inserted another mag and the trigger disconnected. If it had been a bad primer, the trigger would have released normally and the gun would not have fired, but what I got was the feel of an uncocked trigger which would feel like a disconnected trigger.

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I wish I had written down the sequence of events that led up the the mal and exactly what I did right after it happened while everything was fresh in my mind. When it happened, I didn't realize the significance. I just focused on getting the gun going and the situation gradually grew more troublesome as it went on.



Since then I've run about 250 rounds through it without a hint of a problem.



FastSS, Your remark,
"...500 rounds without cleaning isnt going to hurt this thing



I ran 750 in about 4 hours without cleaning... "


is encouraging, thanks. But to be honest, that's exactly what I anticipated about this gun. For some reason, I have a very high expectation of this gun that I haven't had about a gun in a long time.



I hope to run by the range today and if I shoot 200 rounds instead of my normal 100, I'd have 720 total through it; I just may do that.



I'm not one to do torture tests on guns, but since I had this problem, a little 'torture' may be justified in order to demonstrate this was a one-time deal, or that it wasn't.
 

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well now that im not planning on buying a couple of LMT lowers for SBR projects, I'm going to pick up a new non mag safety block cause to be honest, the design of the mag safety, while neat, seems like it could fail pretty easily
 

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Discussion Starter #14
I doubt the mag disconnect will prove to be a liability. I thought I wouldn't like the feature either, but after having it for a while. I wouldn't want to do without it.



For me the mag disconnect is not so much a safety factor as it is a convenience. For example, suppose I have to go into a place where I can't carry - a school, etc. I don't want to leave a loaded, ready to go gun in my car because if some one were to steal my car or gun, it'd be loaded and ready to go. In the past, I unloaded the gun completely and took the mag with me. I had to do something with the round that came out of the chamber, so I started loading the mag one short so I could put the round from the chamber back in the mag. Then when I get ready, I have to rechamber a round. Chambering the same round over and over is going to cause some wear and tear on the nose of the round, esp. in an M&P because of the way a round nose dives into the feed ramp. That means I should cycle rounds to spread out the wear and tear. Now consider the same thing with the mag disconnect.



I remove the mag, leave the round in the chamber, take the mag with me and the gun is inert. When I get back I insert the mag and I'm good to go. I can carry a full mag with one in the chamber this way too, because I don't have to do anything with the round in the chamber.



I now have 720 rounds through my M&P and still haven't cleaned it. I've shot slow and accurate and as fast as I can without a hint of a problem. That's 400 rounds past the point when it malfunctioned. I believe that whatever cause the problem is no longer an issue.
 

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I think the same thing might have happened to me and my M&P 9mm.



I was shooting at the range a couple of weeks ago, in the middle of a magazine.

The gun went blam, blam, blam, tink. I was pretty surprised.

I first removed the magazine to safe the weapon, then racked the slide to examine the cartridge. There was no obvious mark from the firing pin on the primer.

I reloaded the round in the magazine, racked the slide and it fired.

Right now it's kind of a worrisome situation. I hope it either happens allot (so the problem can be identified and fixed) or never again.

This happened around 750 rounds in the gun and with Winchester white box ammo.

fwiw,

Bill
 

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Rice said:
I think the same thing might have happened to me and my M&P 9mm.



I was shooting at the range a couple of weeks ago, in the middle of a magazine.

The gun went blam, blam, blam, tink. I was pretty surprised.


Yeah, but yours went tink. This can be explained bya high primer or something else ammo related. Or even striker issues. If it hadn't made the tink... well then it'd be similar to what tangle is describing.



Giving it some more thought, I wouldn't blame antyhgin for moving the trigger bar, but it is possible something could have wedged the sear in the pulled position, preventing it from catching the striker. Can't imagine what, but it works with the mechanical design of the gun. Most of the clearances on the gun are small enough to keep the big stuff out, but big enough to let the small stuff pass throguh.
 
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