M and p shield issues

[Scubapro13]

First time on this forum.

I am having issue with my shield 40. It will not lock back with a empty magazine or fire with a magazine in it. So far I have tried a new magazine and 100 percent taking it apart and cleaning it but still no luck. Any suggestions?

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[old&slow]

If the firearm will not fire, I would return it to the dealer or S&W.
( some dealers will return the firearm to the manufacturer with in a given period of time. )

There is a lip on the magazine follower that causes the slide to lock after the last round is fired. Not locking back could be the magazine, or new tight springs, or slide stop lever,, or all the above.

 

[Jeppo]

It doesn't sound like this is the problem but it doesn't hurt to check. Numerous new Shield owners have problems that are eventually the fault of not seating the RSA properly. Have you verified that it is seated onto the barrel so the assembly is perfectly parallel to the slide?

 

[Cheapskait]

"It will not lock back with a empty magazine or fire with a magazine in it."

So you're saying that by inserting a magazine, the gun won't fire a chambered round, but will fire a round if you remove the magazine?

I can only think of one thing that would cause that, a badly bent trigger bar. The M&P's, like the Glock's, disconnector is just a bump on the inside of the slide that simply knocks the trigger bar off to the side so you have to reset the trigger to fire again. The trigger bar runs right next to the right feed lip of the mag when inserted, if the trigger bar is moved to the right by the magazine it won't engage the sear.

Just do this:
1. Remove the slide. Make sure the sear lever is raised.
2. Pull and release the trigger. You'll see the sear lowering and raising. (If you push the trigger bar to the right manually, you'll see how the disconnect function works.)
3. Now insert a magazine. Does it touch any part of the trigger bar?
4. Pull and release the trigger. Does the sear raise and lower? If the sear doesn't move, you've got a bent trigger bar. S&W will fix that for you or maybe send you a new trigger bar assy if you're mechanically inclined enough to change it yourself.

 

[Scubapro13]

Correct it absolutely will not fire a chambered round with a magazine in

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[Scubapro13]

"It will not lock back with a empty magazine or fire with a magazine in it."

So you're saying that by inserting a magazine, the gun won't fire a chambered round, but will fire a round if you remove the magazine?

I can only think of one thing that would cause that, a badly bent trigger bar. The M&P's, like the Glock's, disconnector is just a bump on the inside of the slide that simply knocks the trigger bar off to the side so you have to reset the trigger to fire again. The trigger bar runs right next to the right feed lip of the mag when inserted, if the trigger bar is moved to the right by the magazine it won't engage the sear.

Just do this:
1. Remove the slide. Make sure the sear lever is raised.
2. Pull and release the trigger. You'll see the sear lowering and raising. (If you push the trigger bar to the right manually, you'll see how the disconnect function works.)
3. Now insert a magazine. Does it touch any part of the trigger bar?
4. Pull and release the trigger. Does the sear raise and lower? If the sear doesn't move, you've got a bent trigger bar. S&W will fix that for you or maybe send you a new trigger bar assy if you're mechanically inclined enough to change it yourself.

No contact with trigger pulled

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[Scubapro13]

I may have figured out the issue. The tab that catches the magazine when emptied is not catching completely. I can manipulate the magazine to get the gun to function. But the question is how to fix the problem?

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[Scubapro13]

See picture by thumb

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[Rastoff]

Excellent pictures.

Yes, the last picture shows why it might not be locking back after the last round. However, not firing when a mag is inserted is confusing. The mag is not part of the firing sequence.

The first picture shows clearly that the trigger bar is contacting the sear and pivoting it down. Hmmm, this needs more thought.

Here is a list of the parts and their names: M&P Parts Identification

 

[Cheapskait]

Do both mags you tried fail to engage the slide stop tab properly? I don't have a 40 cal Shield to compare, it almost looks like the follower is in there too loosely and is getting pushed over to the side away from the slide lock.

Seems like what you need is a mag you know is good and see if it actuates the slide lock properly.

Hopefully it's just bad mags and if you send S&W photographic proof they're bad, they'll probably just send you some new mags.

The slide lock tab doesn't look bent or damaged, so that's probably not the problem.

The whole not firing with a mag inserted is baffling. Is it a Cali compliant gun with a mag safety?

 

[Scubapro13]

Do both mags you tried fail to engage the slide stop tab properly? I don't have a 40 cal Shield to compare, it almost looks like the follower is in there too loosely and is getting pushed over to the side away from the slide lock.

Seems like what you need is a mag you know is good and see if it actuates the slide lock properly.

Hopefully it's just bad mags and if you send S&W photographic proof they're bad, they'll probably just send you some new mags.

The slide lock tab doesn't look bent or damaged, so that's probably not the problem.

The whole not firing with a mag inserted is baffling. Is it a Cali compliant gun with a mag safety?

Nope I figured it was the mag so I just bought a new one and it is still doing the same thing. I can manipulate the magazine when I put it in to engage it

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[Scubapro13]

If I push down on the magazine as I am putting it in like this it it will work fine but if I stop putting pressure there is nothing

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[Scubapro13]

I wish I would have taken a picture of the new magazine but I'm sure its wearing this corner down?

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[swsig]

In picture #1, the magazine appears to be in its proper location. However, in picture #2, the magazine is pushed far enough to the right so the follower is not making contact with the slide stop tab. That explains why your slide will not lock back. If it's pushed that far to the right, it may be pushing against the trigger bar, causing it to function improperly. Thus, the no-fire situation with a magazine inserted. There could be something inside the magazine well that is causing your magazines to be shoved too far to the right. Maybe the well itself was not formed correctly in the mold. If you can't find some obvious type of correctable defect inside the well, you may need a new grip assembly.

 

[Cheapskait]

Yeah, in the first picture, the ejector appears to be just inside of the gap between the feed lips while in the second it looks like it's outside. When the mag is pushed over to the right as far as it will go does it touch the trigger bar then?

Away, you shouldn't have to put up with this BS, send it back.

 

[swsig]

I just field stripped my Shield 9 to check the trigger bar. By putting just the slightest amount of lateral pressure on it, as your wayward magazines do, the bar was forced far enough to the right that the sear block release tab would not make contact with the sear block button, and the trigger loop would not make contact with the sear. Either one of these events would prevent your Shield from firing. If you can't find a consistent way to get your magazines inserted into the correct position, Cheapskait is right, your Shield needs to go back to S&W.

 

[Cheapskait]

Yeah, and when you contact them include a link to this thread. They should be embarrassed that a pistol that's apparently WAY out of spec slipped through QC and QA.

 

[Scubapro13]

I was hoping to be able to fix it but it looks like I may have to send it in. How long does that take it was my edc?

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[mnshutterbug]

How long does that take it was my edc?

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If that was your edc, it's a good thing you never needed it since it wouldn't even fire.

 

[Scubapro13]

Never had any issues probably have 1500 round through it

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[Dad_Roman]

Never had any issues probably have 1500 round through it

This seems to be an oddity that it malfunctions in the middle of its life span. Right outta the box?...sure, but not after 1500 rounds.

Plenty of time over the weekend, no rush to pack it up.

This one's above my pay grade. I recommend you wait for Rastoff to finish thinkin about it. He will probably come up with something

 

[Smakmauz]

couple things...

Have you verified that there isn't some gunk or something binding up the slide stop a bit? doesn't take much resistance for it to fail to lock back on an empty mag.

Does the weapon have a magazine lock out feature?

Did you ever check what Cheapskait said about chambering a round and trying to fire without the mag in the well? obviously if you have one with a mag lockout this won't work anyway... but this will be a good diagnostic test if you don't have that feature.

also I don't see that you specifically answered him about weather the sear is properly moving up and down when you have it field stripped and pull the trigger.

 

[swsig]

...the trigger loop would not make contact with the sear. Either one of these events would prevent your Shield from firing....

I went back to your picture #2, and upon closer inspection, I can see that your trigger loop is offset from the sear far enough to the right (outside) that it won't make contact. Your gun won't fire when that happens.

For some reason, your magazine well has too much "wiggle room" that allows your magazines to be inserted too far to the right so that they interfere with the trigger bar. When I checked the inserted magazine on my Shield 9, I could not push it far enough to the right to affect my trigger bar. There must be some manufacturing defect in your Shield to allow that that to happen.

 

[Scubapro13]

couple things...

Have you verified that there isn't some gunk or something binding up the slide stop a bit? doesn't take much resistance for it to fail to lock back on an empty mag.

Does the weapon have a magazine lock out feature?

Did you ever check what Cheapskait said about chambering a round and trying to fire without the mag in the well? obviously if you have one with a mag lockout this won't work anyway... but this will be a good diagnostic test if you don't have that feature.

also I don't see that you specifically answered him about weather the sear is properly moving up and down when you have it field stripped and pull the trigger.

To answer both of them question it will fore a chambered magazine and yes the sear is moving up and down properly. I completely striped the gun yesterday before posting

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[Scubapro13]

To answer both of them question it will fore a chambered magazine and yes the sear is moving up and down properly. I completely striped the gun yesterday before posting

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*questions, *fire. Dann small buttons

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[Smakmauz]

I went back to your picture #2, and upon closer inspection, I can see that your trigger loop is offset from the sear far enough to the right (outside) that it won't make contact. Your gun won't fire when that happens.

I can see this as well... though it seems not very possible that a problem like this could stay hidden for 1500 rounds if it was a defect right from the factory

would you be able to post a pic that is taken from above the field stripped frame with no magazine looking down on top of the internals? basically just like the first one but with no mag in it. as clear as possible with a lot of light would be very helpful

we'll figure this out if we can!

 

[rwsmith]

With THAT kind of malfunction.....

Not firing with a magazine in is a catastrophic failure to operate in my book. I wouldn't mind trying to figure it out myself, but it would definitely go back to S&W if there is no quick resolution. You can't fire a shot, put in the mag, rack, remove the mag, fire and repeat.

 

[NewToGuns17]

Have you had the gun apart? In post #12, it looks like the roll pin below the takedown lever is pushed out slightly? I'm curious how after 1500 rounds this shows up in the gun, but i don't put anything past any product, ever. I would as well say a trip to S&W and see if they'll replace those followers that are chewed up.

 

[Scubapro13]

I can see this as well... though it seems not very possible that a problem like this could stay hidden for 1500 rounds if it was a defect right from the factory

would you be able to post a pic that is taken from above the field stripped frame with no magazine looking down on top of the internals? basically just like the first one but with no mag in it. as clear as possible with a lot of light would be very helpful

we'll figure this out if we can!

See pictures

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[Scubapro13]

Another good picture. If #1 is not correctly sitting on the magazine which forces the magazine into spot #2 which doesn't allow it to engage the sear #3

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