Weird Trigger reset issue

[mhuxtable]

So my basic question is can a mag extension cause a trigger not to reset?

I recently got +10 mag extensions from Taylor Freelance for my M&P CORE pistol. It's tricked out to an open pistol.  It's just a fun gun.  The pistol has the Apex trigger kit in it. It's worked flawlessly up until today.

Today was the day to test these TF +10s.

Everything fed great. Except I had 5 or 6 rounds that didn't fire because the trigger didn't reset. The gun appeared to be in battery, but pulling the trigger did nothing. No click, no nothing. I'd rack that round out and it'd fire just fine. 

None of the rounds appear out of spec. It's the usual ammo I use. 124gr S&B 9mm.

Is this a magazine issue? or something unrelated and cooincidental?

Any ideas?

[Bench]

2 hours ago, mhuxtable said:

So my basic question is can a mag extension cause a trigger not to reset?
I recently got +10 mag extensions from Taylor Freelance for my M&P CORE pistol. It's tricked out to an open pistol.  It's just a fun gun.  The pistol has the Apex trigger kit in it. It's worked flawlessly up until today
Everything fed g.reat. Except I had 5 or 6 rounds that didn't fire because the trigger didn't reset. The gun appeared to be in battery, but pulling the trigger did nothing. No click, no nothing. I'd rack that round out and it'd fire just fine.
Is this a magazine issue? or something unrelated and cooincidental

I had a similar issue but with new mags in a M&P 9 Pro. The new mags were 15 rnd+ (no extensions)and at the range the trigger wouldn't reset after EACH round fired. I had to put the factory trigger return spring in and all went well...mostly, only one failure to reset in 100 rnds, still not acceptable. It's still a mystery since the frame and trigger body is CLEAN!! I ordered an Apex comp trigger only (not the whole 'shebang' kit) so I'll see if that makes any difference. (I'm not too excited about their extra power sear plunger spring but I'll see what happens). Looking forward to hearing what others experiences might be with issues like these.

Edited December 20, 2018 by Bench

[BJB]

Sounds like sear flutter. Replace the sear spring. I had the same issue after putting Apex in my M&P. The Apex sear spring worked great for a couple thousand rounds but got weak and introduced flutter. I put the factory sear spring back in under the Apex sear and the gun went back to 100% reliability.

[mhuxtable]

Thanks guys I'll look into it.  Also had someone say to look into the trigger bar loop. 

 

Kinda weird everyone sings the praises of the apex kit but these issues now seem common that i'm looking into it

[Bench]

48 minutes ago, BJB said:

Sounds like sear flutter. Replace the sear spring. I had the same issue after putting Apex in my M&P. The Apex sear spring worked great for a couple thousand rounds but got weak and introduced flutter. I put the factory sear spring back in under the Apex sear and the gun went back to 100% reliability.

So what the heck is sear flutter in other terms than the sear doesn't work??? Thanks.

[BJB]

Google M&P sear flutter and you'll learn all you want to know.

Sear flutter is when the sear spring gets too weak and is not up to the task of timely resetting the sear upon the slide reciprocating.  When the slide reciprocates the trigger bar is pushed to the side allowing the sear spring to push the sear back up and catch the striker upon the slide closing, thus arming it for the next shot. A weak sear spring doesn't allow the sear to be positioned up in time to catch the striker, or it flutters on the weak spring and is not firmly is position. The striker goes by before the sear can catch it, it misses. Now you have a dead trigger but everything else worked fine; hull extracted, live round in the chamber, etc. This was more common on earlier M&Ps because they had smaller sear springs. They changed the sear springs around 2012 or thereabouts. The only times I've known of this to happen on recent M&Ps is with Apex parts installed. The Apex sear spring is a weaker spring to help lower the overall trigger pull. When it weakens further with use the sear flutter can occur just like the early model M&Ps. Put the factory sear spring back in under the Apex sear. You won't notice something like 1/2 an ounce of added trigger pull.

Edited December 20, 2018 by BJB

[Bench]

41 minutes ago, BJB said:

Google M&P sear flutter and you'll learn all you want to know.

Sear flutter is when the sear spring gets too weak and is not up to the task of timely resetting the sear upon the slide reciprocating.  When the slide reciprocates the trigger bar is pushed to the side allowing the sear spring to push the sear back up and catch the striker upon the slide closing, thus arming it for the next shot. A weak sear spring doesn't allow the sear to be positioned up in time to catch the striker, or it flutters on the weak spring and is not firmly is position. The striker goes by before the sear can catch it, it misses. Now you have a dead trigger but everything else worked fine; hull extracted, live round in the chamber, etc. This was more common on earlier M&Ps because they had smaller sear springs. They changed the sear springs around 2012 or thereabouts. The only times I've known of this to happen on recent M&Ps is with Apex parts installed. The Apex sear spring is a weaker spring to help lower the overall trigger pull. When it weakens further with use the sear flutter can occur just like the early model M&Ps. Put the factory sear spring back in under the Apex sear. You won't notice something like 1/2 an ounce of added trigger pull.

Thanks BJB, It's interesting that the M&P's aren't really tolerant of much change for competition use. As I posted previously with a new trigger Apex sends an extra power sear spring. On a side note have you done any work to the M&P sear/striker engagement measurement ie. reducing the sear height (ala Burwell)?

Edited December 20, 2018 by Bench

[BJB]

No, I haven't messed with the sear/striker engagement. I know fellas who have and what they ran into were reliability issues. I wouldn't worry too much about it.  When I started this sport I used to worry about tweaking triggers just so and making them as lite as possible but in the end that was counter productive. I realized I was trying to "buy skill".....and reliability issues would rear their ugly head in matches too. There is one way and one way only to improve at the shooting game and that is through practice, dry-fire, etc. No lite trigger or special soft reload will improve your skill. I actually found I don't like a super lite trigger and on my M&P I put the factory springs back in. The Apex sear geometry is good, I just found the springs too lite for my tastes. I don't care necessarily how lite a trigger is as long as it is crisp and consistent on the break with minimized over travel. I don't even care about the pre-travel. On reloading I also played around with loads right at power factor. I found them not as accurate in general as loading to around 134-135 power factor and the lite loads didn't improve splits or anything anyhow.

 

Long story short is that initially I tried to "buy skill" or "game skill" by thinking I was getting an edge on a trigger, etc. But, my skill never really improved until I legitimately started dry-firing in earnest. All my triggers don't really have tons done to them anymore. A polish is always good as you're not changing anything though. Some work can be good, depending on the gun, but don't over do it. My Stock II Extreme has nothing changed at all, just polish as per "MemphisMechanic" and that is what I'm nearing A class with right now. All the GM, M, & A shooters I know didn't improve because of a lite trigger, or soft reload, etc. They improved their skill via dedicated practice and experience. When we chit-chat it's rarely about how lite a trigger is, but rather about drills & practice & stage break-down, etc.

 

That's my take and what works for me.  All shooters are different though.  I spent lots of time early on tying to gain that special edge.  In one aspect it taught me plenty of lessons, but in another aspect I wasted lots of time playing around that I could have invested into practice.

 

I'll shut-up now as I'm straying way away from the original topic as posed by "mhuxtable".

[Bench]

1 hour ago, BJB said:

.....and reliability issues would rear their ugly head in matches too. 

Thanks, I'd rather have a reliable gun with a factory trigger pull weight than a semi reliable gun and light trigger pull and that's where I"m headed since dry-fire is well underway in my routine.

[pete627]

18 hours ago, mhuxtable said:

> snip <
Is this a magazine issue? or something unrelated and cooincidental?
> snip <

Soooooooo ... if you try a magazine w/o the extension does the trigger reset OK??

I am only asking ... because ... the extension (base pad) may be allowing the magazine to seat at a different height than it did previously. If you remove the slide and insert a magazine you can see how close it comes to the trigger bar ...

IMHO ... If the magazine is "NOW" touching the trigger bar it could prevent it from moving freely and easily cause the problem you are describing. 

Edited December 20, 2018 by pete627
edit: I kan spel ...

[mhuxtable]

36 minutes ago, pete627 said:

Soooooooo ... if you try a magazine w/o the extension does the trigger reset OK??

I am only asking ... because ... the extension (base pad) may be allowing the magazine to seat at a different height than it did previously. If you remove the slide and insert a magazine you can see how close it comes to the trigger bar ...

IMHO ... If the magazine is "NOW" touching the trigger bar it could prevent it from moving freely and easily cause the problem you are describing. 

 

I will check that out! Thank you.  Admittedly I'm not completely fluent in how all the inner workings of a pistol interact totally.  So things like this are helpful.  

 

If it WERE touching the trigger bar for some reason, how could that be remedied?

 

It's odd really.  It only did it about 5 times in 130 rounds. But that's about once per mag & that's too much. 

[pete627]

33 minutes ago, mhuxtable said:

 

I will check that out! Thank you.  Admittedly I'm not completely fluent in how all the inner workings of a pistol interact totally.  So things like this are helpful.  

 

If it WERE touching the trigger bar for some reason, how could that be remedied?

 

It's odd really.  It only did it about 5 times in 130 rounds. But that's about once per mag & that's too much. 

You can just bend the bar slightly. You will see ... Just take the slide off ... put a mag in and pull the trigger and you can see what is going on.

There are lots of photos and videos on these things ... from Apex and like this one (link below) (is a good example to see what it looks like in there so you will feel comfortable taking a look).  https://www.youtube.com/watch?v=dP4e1ZvI4GY

[mhuxtable]

well I tried opening the trigger bar loop a little and replacing the sear spring from the Apex to the OEM....the problem today was worse than before.  Almost every 2nd - 5th round had the trigger fail to reset. 

 

So I'm just gonna take it to the gunsmith after christmas. 

[BJB]

9 hours ago, mhuxtable said:

So I'm just gonna take it to the gunsmith after christmas. 

 

Before you go that route you might take a look at the following and see if it is possibly the issue.  These images were sent to my by Apex when I was having my trigger reset issue and we were trying to figure it out.  See if the trigger bar is touching the inside of the right side slide stop lever upon reset and producing side load pressure, thus messing with reset timing. Take the slide off, pull the trigger & hold, push the bar to the side for reset just like would happen upon slide reciprocation.  See if it touches the inside of the slide stop lever and is binding.  If it isn't binding then of course this isn't the issue. If it is binding laterally then this could possibly be the issue.  If your slide stop lever is the Rev B type then it will have a bump on it on the inside right where the binding would occur.  You can either get a Rev A slide stop lever which doesn't have the bump or simply file that bump flush.

 

 

 

Apex explained it better than me.  I'll try to find the old e-mail and copy/paste it below:

     "The first area that may be causing the reset issues you are experiencing may be due to too much side load pressure being applied to the Trigger Bar due to the Rev B Slide Stop Lever which has a “bump” on the inside that can push the Trigger Bar in and not allow it to properly flex as it is supposed to.  The appropriate amount of lateral tension needed for the Trigger Bar to reset should be 2.0 lbs or less.  You can check the lateral tension weight by removing the Slide, pulling the Trigger to the rear, placing a Lyman Gauge on the Trigger Bar close to where the Trigger Bar Loop and Sear engage each other, and while continuing to hold the Trigger to the rear then use the Lyman Gauge to pull the Trigger Bar towards the frame to simulate the reset while checking how much pressure is needed on the Lyman Gauge for the Trigger Bar to reset.  If it takes over 2.0 lbs of pressure for the Trigger Bar to reset then it is recommended to either replace the Rev B Slide Stop Lever with a Rev A Slide Stop Lever or file down the “bump” on the Rev B Slide Stop Lever that is making contact with the Trigger Bar.  I’ve included a photo of where to remove the material from the Rev B Slide Stop Lever."

 

The only other things I can think of off hand are:

1) Is your gun a newer production or older production gun?  Pre 2012?  If it's a pre 2012 model then it will have a different sear housing block with a smaller sear spring.  An updated sear housing block can be dropped in easy as pie.

2) Do you have the Apex RAM (reset assist mechanism) installed?  If so, remove it and run the gun to see if there is any change.  The RAM functions with the tail of the trigger bag dragging laterally across the RAM.

3) Is your sear housing block firmly in the gun or does it wiggle a little?  Grab the ejector and wiggle up/down & side-to-side. Does the actual sear housing block move any? If it does move some then it can also be moving up a little upon recoil, thus changing the sear/trigger bar engagement and messing up the timing. 

 

[mhuxtable]

6 hours ago, BJB said:

 

Before you go that route you might take a look at the following and see if it is possibly the issue.  These images were sent to my by Apex when I was having my trigger reset issue and we were trying to figure it out.  See if the trigger bar is touching the inside of the right side slide stop lever upon reset and producing side load pressure, thus messing with reset timing. Take the slide off, pull the trigger & hold, push the bar to the side for reset just like would happen upon slide reciprocation.  See if it touches the inside of the slide stop lever and is binding.  If it isn't binding then of course this isn't the issue. If it is binding laterally then this could possibly be the issue.  If your slide stop lever is the Rev B type then it will have a bump on it on the inside right where the binding would occur.  You can either get a Rev A slide stop lever which doesn't have the bump or simply file that bump flush.

 

 

 

Apex explained it better than me.  I'll try to find the old e-mail and copy/paste it below:

     "The first area that may be causing the reset issues you are experiencing may be due to too much side load pressure being applied to the Trigger Bar due to the Rev B Slide Stop Lever which has a “bump” on the inside that can push the Trigger Bar in and not allow it to properly flex as it is supposed to.  The appropriate amount of lateral tension needed for the Trigger Bar to reset should be 2.0 lbs or less.  You can check the lateral tension weight by removing the Slide, pulling the Trigger to the rear, placing a Lyman Gauge on the Trigger Bar close to where the Trigger Bar Loop and Sear engage each other, and while continuing to hold the Trigger to the rear then use the Lyman Gauge to pull the Trigger Bar towards the frame to simulate the reset while checking how much pressure is needed on the Lyman Gauge for the Trigger Bar to reset.  If it takes over 2.0 lbs of pressure for the Trigger Bar to reset then it is recommended to either replace the Rev B Slide Stop Lever with a Rev A Slide Stop Lever or file down the “bump” on the Rev B Slide Stop Lever that is making contact with the Trigger Bar.  I’ve included a photo of where to remove the material from the Rev B Slide Stop Lever."

 

The only other things I can think of off hand are:

1) Is your gun a newer production or older production gun?  Pre 2012?  If it's a pre 2012 model then it will have a different sear housing block with a smaller sear spring.  An updated sear housing block can be dropped in easy as pie.

2) Do you have the Apex RAM (reset assist mechanism) installed?  If so, remove it and run the gun to see if there is any change.  The RAM functions with the tail of the trigger bag dragging laterally across the RAM.

3) Is your sear housing block firmly in the gun or does it wiggle a little?  Grab the ejector and wiggle up/down & side-to-side. Does the actual sear housing block move any? If it does move some then it can also be moving up a little upon recoil, thus changing the sear/trigger bar engagement and messing up the timing. 

 

 

Your photo links are broken so I can't see them.  
 

I did a looksie and it doesn't appear the bar is touching the mags.  But I could be wrong I guess?  I'll have another look.  I don't have a weight guage to tell how much pressure it takes to reset.  

 

How can I find if mine is a pre 2012?  It's a Pro Series with a CORE slide, 5 inch barrel. 

 

No Apex RAM

 

From the last time I took the gun apart the sear block seems very very snug. But I'll check again. 

 

[BJB]

4 hours ago, mhuxtable said:

I did a looksie and it doesn't appear the bar is touching the mags.  But I could be wrong I guess?  I'll have another look.  I don't have a weight guage to tell how much pressure it takes to reset.  

Not the mags....  If there is binding upon reset it will be the trigger bar binding against the inside of the right hand side slide stop lever.  I'll attach the pictures again here but use a different method.

 

4 hours ago, mhuxtable said:

How can I find if mine is a pre 2012?  It's a Pro Series with a CORE slide, 5 inch barrel. 

If you have a CORE it is not a pre 2012.

[mhuxtable]

so i looked at it and I don't have that type of slide stop lever with the nub but it does seem as if the trigger bar coud be making contact with the slide stop a bit.  How would I fix this?

[BJB]

11 minutes ago, mhuxtable said:

so i looked at it and I don't have that type of slide stop lever with the nub but it does seem as if the trigger bar coud be making contact with the slide stop a bit.  How would I fix this?

If it's just barley touching on reset then this is likely not to be the problem. If it is touching upon reset and you can see the trigger bar flexing some then this might be the problem.  You might try to file the inside of the slide stop lever where the contact occurs, even though you evidently don't have the Rev B lever.  File a lot if you want to, especially if you are right handed because if so then the right side slide stop lever won't get used by you during operation of the gun

 

All these possible things I have mentioned are what I have personal experience with and I was just trying to save you some heartache in case it actually was one of those scenarios. My M&P reset problem fix was as simple as going back to the factory sear spring and the gun instantly went back to 100% reliability, and it's had around 10,000 rounds through it since without a single issue of any kind. If you're having reset issues due to some other factor then I'm afraid I won't be much help. For the life of me I just don't see how you adding mag extensions could instigate reset issues.  I think the reset issue just coincidentally showed up when you added the mag extensions to confuse the situation.  It will hurt nothing to remove the mag extensions and see how she runs however. Who knows?

 

Finally though, if nothing works and you still have reset issues call Apex and deal with them before bringing your gun to a gunsmith.  Apex is very good to work with you on your gun issues that might possibly involve their product. Even if it doesn't involve the Apex parts I bet they can steer you in the right direction. These dudes intimately know a M&P and how everything works inside there. I don't know your gunsmith but I'd definitely call Apex before just bringing the gun to a gunsmith who may or may not have lots of experience with M&Ps.