I am still relatively new to guns and to shooting but am really learning and loving it. I bought a M&P Shield .40 S&W for CC back in the spring but had no place nearby to shoot until our county opened a new range in October. The gun shoots very accurately, though I sometimes don't.

By now, the gun is well broken in, having put more than a thousand rounds through it. Over the first couple of months (October-November), its performance was flawless, with no FTFs, FTEs, etc., over that period.

However, over the last two months, a serious problem has developed that is now beginning worsen. About once in every four to five magazine magazine reloads, I began to experience a FTF on the very first round that would be loaded from the mag. When this happens, one of two things will occur: 1) I will have what I call a squishy or "dead" trigger (with the round chambered, the trigger pulls all the way back without any resistance and without a "click"), OR b) the trigger will "click" (it will feel and sound like a normal trigger pull) but the round does not fire. Upon inspection, that round will have an impression from the striker (or firing pin?). When the FTF round (the one with the impression) is reloaded into the mag (in any position), it will subsequently fire, so it doesn't seem to be an ammo issue.

On my recent trips to the range since New Year's, however, I have had this problem occur on the first round loaded from a mag and then the FTF recurs four or five times in a row before I can finally get the gun to fire a round. Once the weapon finally "gets in sync" and begins firing, the gun would fire forever, I think, if I had an infinite mag. And again, the problem may not recur for another three, four, or five mags or more. And the failure to fire issue never occurs once the first round in a mag is fired, and the gun is in semi-automatic mode. It seems as though the trigger/striker mechanism just sporadically fails to reset.

For purposes of troubleshooting, let me review what I have done and know already:
1) The gun is properly broken in with over 1000 rounds through it.
2) I have used ammo from multiple manufacturers (for example, today was Remington).
3) The weapon is cleaned every 100 rounds, or every two trips to the range (or once a week, whichever comes first).
4) I have taken care to make certain that I was not guiding the slide back into battery when manually racking the first round of a mag.
5) I have taken care to make sure I wasn't racking too "short" or too gently.
6) The problem occurs whether I manually rack or if the slide releases by itself upon insertion of the magazine, which it sometimes does.
7) I have tracked my mags (and stretched mag springs) to see if the problem only occurs with a specific mag (I have five) but found no pattern.

I would appreciate any insights that vastly more experienced and knowledgeable shooters here on the forum may have. I hope I have not spoken too gun "illiterately" and that I have adequately described the problem. Thanks in advance from this newby.

Dead trigger sounds like it may not have been fully into battery. Pull the slide fully back and release it. Check that the rear of the slide is flush with the frame. The primer mark without firing is a light hit. I would suggest pulling the striker out, checking it, clean the striker and striker bore, and reinstall. See the attached video for how to remove the striker.

Bob

https://www.youtube.com/watch?v=6vJQuxBVplY

I believe that robkarrob has identified the likely sources of the problem. I would wager that your recoil spring has weakened and is not returning the slide to full battery. When the slide is ever so slightly out of battery you are getting the light strike and when it is more than slightly out of battery, you are getting the dead trigger. Inspect and replace the recoil spring.

The reason the problem first began happening on the first round chambered is that the nearly fully loaded magazine is putting maximum upward pressure on the slide's loading ramp and thereby making the recoil spring work harder to fully close the slide. Later on when the recoil spring's performance deteriorated further, the problem began happening when there were fewer rounds in the magazine (and less upward pressure on the slide).

The variability of the problem occurring is also influenced by the temperature of the gun.

P.S. Let us know if you find gunk in the striker channel or some other cause of the problem. Oh, and please do not stretch your mag springs. A metallurgist on Ballistic Radio discussed how that can lead to broken mag springs.

I had similar issues of light strikes with my 9 - my problem was crud in the striker channel.

I don't know about light strikes, but I think others are right about the "squishy", or "dead" trigger. Slide not fully forward.

Robkarrob, for a thorough cleaning, is there a way to easily remove that plastic insert inside of the slide? Some people use a water-based gun cleaner and I could envision that rust might form in the space between the plastic liner and the slide if fluid is trapped in there. Of course the last thing I want to happen is for the surface of the plastic liner to get marred using some type of removal tool.

Thanks for the insights, guys. I have enjoyed reading through the threads on the forum and am learning lots from people like you with way more experience than I possess.

I have been playing with racking the slide more "assertively", and it certainly could be that, as aggressive as I thought I was being, it actually pulls back much further than I thought. So despite my focus on it, it certainly could be that it is often not completely in battery.

Bob, I enjoyed the video and pulled the striker out this evening and cleaned both it and the bore throughly. It was really grimy. Perhaps that will help with the light strikes.

Headed to the range tomorrow, so I will keep tabs on the issue and report back.

Will also leave the mag springs be. Thanks, again.

Have waited until I made three or four trips to the range to report back. After cleaning the striker and striker bore thoroughly and making certain to thump myself in the chest with my off-hand after racking the slide, I have had no replications of the "squishy" trigger or soft strike problems. I appreciate the help.

I was too late to offer the helpful advice above but wanted to point out that absent pictures you did an excellent job of describing the problem along with your level of experience and the various symptoms and diagnostics steps taken.
The forum members above stepped up and made very good suggestions which you followed and resolved your issue AND reported back here so that anyone who comes across this thread can benefit.
Also nice to see thread where no one jumped on you for being new or blaming you for improper operation etc.
All of which is why I enjoy being a part of this community.

Does it do it if the slide is locked back and you release the slide by pulling the slide back and and letting go as the manual states?

Oldcoach, I just bought a new Shield 9mm with no safety and had the EXACT SAME problem at the range yesterday as I fired 200 rounds straight out of the box for the first time. It happened 3 times at the beginning of refilled mags, after it did not fire I would pull on the trigger again and it would fire. I fired 200 rounds through it with Blazer Brass ammo. You did a great explanation of your problem and I will try the recommended solution from your forum answers. HAVE YOU HAD anymore problems with your shield? Also, thanks to the great experts on this forum in helping with the solution. jr235
[email protected]

P.S. sounds like you are an old coach with that forum name... I am an old retired high school football coach.

You might check the bolt face around the firing pin for crud build up and also the chamber were the bolt hits up against it. Enough build up of dirt can cause a light strike of the firing pin if only a bit of dirt gets packed in tight causing the bolt not to close enough.