Did I break my Shield? It won't fire consistently after reassembly *VIDEO*

[Jabbit]

I had a leftover trigger spring from my Apex FSS kit from another gun (didn't use the 5.5# green one) so I decided to put it in my Shield 9mm.

Stripped the gun down, installed the new spring, then put everything back together. This is the result - M&P Shield Trigger Issue - YouTube (sorry for the poor quality, used my phone. I cycle it again after the first "fire")

What did I do wrong? I took it apart, checked everything, and put it back together. Still does it. Any advice? I can't imagine it is the spring but I guess I should switch back? I was told by a couple different gunsmiths that the spring was OK to use. This is a MA-compliant Shield with the ONLY change being the use of the green spring from this kit - LINK

 

[delphidoc]

I am by no means a smith. It looks to me like you're able to pull the trigger repeatedly without racking the slide. I would guess your striker safety isn't working. Did you replace the rear sight or install an Apex USB?

 

[Bkreutz]

You said a couple of smiths told you that you could use the spring but did you ask Apex? That would be where I would start. Then put the old spring back in and see if it works. I'm thinking you've got something out of place in the trigger block and what you're hearing is something catching as you pull the trigger. You might have to have someone else look at it but I'd try putting the original spring back in first.

 

[RobzGuns]

I'd go a step further and say to go back to the original spring first, to see if it works.
If it doesn't work with the original spring back in it, you know that something other than the spring messed it up.
If it does work with the original spring back in it, you now know it's the 'leftover' spring.
THEN call Apex and ask what they think about using the spring.

 

[Rastoff]

This is not a spring issue. The spring you replaced is the trigger return spring. It's what pulls the trigger forward after firing. Otherwise the trigger would just stay back.

The video is adequate to see what the issue is, but there is a better angle for us. Take the slide off and take the video again from the stop. I want to see if the trigger bar loop is engaging the sear.

Here's a video I made on how the trigger works: http://www.youtube.com/watch?v=5_RoDAOQGnQ A video of yours from this same angle should help us determine what's wrong.

 

[Jabbit]

I'll post another video with the slide off, thanks for the link to your video.

Apex actually said that using the trigger return spring would make my trigger pull heavier - they said no issue in using it however. No idea how it could physically make the trigger heavier but that is what I wanted to see.

I'll make a video of the current situation, put the factory spring in, then see what happens. Thanks for all the help.

 

[randyr5]

From the sound when you pull the trigger, my guess is that the trigger bar loop is sliding off of the sear before the striker is released. That's why it is resetting after each pull. When the striker finally did release, it did not reset without a rack of the slide. I don't know if this would make a difference, but did you make sure to install the spring on the trigger bar with the open end facing up?

 

[Rastoff]

No idea how it could physically make the trigger heavier...

The trigger is being pulled against this spring. So, if the spring you used is heavier than stock, the trigger pull will be heavier.

That spring cannot cause the issue you're having. It must be something with the way the gun was reassembled.

 

[Jabbit]

I don't know if this would make a difference, but did you make sure to install the spring on the trigger bar with the open end facing up?

I tried both ways, happened each time.

The trigger is being pulled against this spring. So, if the spring you used is heavier than stock, the trigger pull will be heavier.

That spring cannot cause the issue you're having. It must be something with the way the gun was reassembled.

Sorry, my quote was not accurate. The spring is lighter than stock, which is why I don't know why it would be heavier. I'll double check assembly and hopefully I can figure it out. If not, I'll post another video.

 

[randyr5]

With the slide off, pull the trigger and make sure that the trigger bar loop stays underneath the sear. If the loop is bent, it can slide of of the side of the sear, which is not what you want.

 

[Jabbit]

Trigger bar loop stays underneath the sear the whole time, but the trigger doesn't "spring back" to the normal position. I put the factory spring back in and I have the same issues. My phone won't take a clear enough video to show the internals. Will S&W take a look at my gun under warranty even though I may (most likely did) bugger something up?

With the slide off, pull the trigger and make sure that the trigger bar loop stays underneath the sear. If the loop is bent, it can slide of of the side of the sear, which is not what you want.

 

[Rastoff]

Will S&W take a look at my gun under warranty even though I may (most likely did) bugger something up?

Most likely they will. Call or email them and tell them what you did. They will probably say they need to look at it and you'll need to send it in. They should send you a free shipping label.

I wish you were closer. I'm sure we could fix this right up if I could just see the gun.

 

[Jabbit]

I wish you were closer. I'm sure we could fix this right up if I could just see the gun.

Thanks. I don't mind that I broke it, but I'm irritated that I can't figure out how to fix it. Breaking something and not learning from it isn't fruitful. Tonight I plan to strip it down completely, clean it up, and put it back together very carefully. Maybe I can figure it out. It feels like the trigger itself is catching on something or there is a bit of binding in the trigger bar.

 

[Rastoff]

I don't mind that I broke it, but I'm irritated that I can't figure out how to fix it. Breaking something and not learning from it isn't fruitful.

Very well said. I feel the same way. If I were in your shoes I'd be going crazy trying to figure it out.

Tonight I plan to strip it down completely, clean it up, and put it back together very carefully. Maybe I can figure it out. It feels like the trigger itself is catching on something or there is a bit of binding in the trigger bar.

This is a good plan. I too think something is interfering with the trigger bar. There could also be something up with the sear.

 

[ammodave]

If I had caused the problem, I wouldn't expect S&W to make it right on their dime. I'd just take it to my local smith and pay him to fix it.