Light primer strikes, slide out of battery on Shield 9mm v1.0

[jawman]

Warning: long post ahead. TL;DR: Was getting light primer strikes on Shield, removed striker assembly, it was dirty, I cleaned it, fingers crossed that fixes the issue.

So I have an M&P Shield9 v1.0 with APEX DCAEK and AEK trigger installed. It was installed by a professional gunsmith/M&P armorer when the gun was brand new, before it got to me (I purchased the gun, parts, and install service brand new all at once). Anyway, I've had this pistol since July 2017. In the time I've had it I've put approximately 1,000 rounds through it, with absolutely zero malfunctions of any kind, regardless of ammo. Well, that all changed recently. I was at the range with some family during Christmas, and I had some light primer strikes resulting in a failure to fire, about 3-4 light primer strikes within 200 rounds. At first I thought it may be the ammo since it was a really cheap Remington range ammo, and the gun was clean (I always clean my gun after every shooting session, so I'm always starting with a clean gun each session). After we finished up at the range and got home, I field stripped and cleaned the gun very diligently.

Fast forward to the next shooting session a month later, I'm getting more of those dreaded light primer strikes resulting in failure to fire. This time though I was using a multitude of ammo: Federal HST, Speer Lawman, and your standard Federal ammo from Walmart that comes in the red box. In 250 rounds, I had 4 light primer strikes, and it happened with each type of ammo. It would happen at random: first round, middle of a mag, didn't matter when it just happened randomly. This was very concerning given the multitude of quality ammo, so at that point I ruled out ammo as the factor and figured it has to be the gun.

Another thing I noticed during this session is that whenever I insert a fresh mag, I always give it a good smack with the heel of my hand to make sure it's seated all the way. Well I noticed this caused the slide to pop out of battery, which has never happened to me before with this gun in the 19 months I've owned it. For example, if I want +1 in the chamber and top off the mag, I rack a round into the chamber, eject the magazine, top the mag off with the last round, and then reinsert it back into the gun and give it a smack to make sure it's seated all the way. When I did that, the smacking of my hand on the bottom of the mag was forcing the slide to jump out of battery. Picture here: https://imgur.com/daJGcxK

After I finished shooting, I talked to the store's gunsmith on my way out. He said it was probably the Apex springs because Apex doesn't use good springs and told me to get Wolff springs instead. I told him the Apex parts were installed by a professional gunsmith who is also an M&P armorer, and he was like oh okay, hmm (with a perplexed look on his face). He said to give the gun a good cleaning (which I already did prior to the shooting session) and see if it happens again, and that he could look at it. He couldn't look at it that day because he was busy and I was on my way out anyway. He also said not to top the mag off and +1 in the chamber because it can damage the gun because it's putting to much pressure on everything, and that he got lots of police trade ins of other guns with similar problems...

I get home that night and research M&P Shield light primer strikes. Did the usual internet sleuthing reading through various forums, and most people said to disassemble and clean the striker and firing pin. All this time I was under the assumption that the rear sight had to be removed in order to do this, and never realized how easy it actually is to do. I've never once done this to the gun until now. Credit to this video here for teaching me how to remove and reassemble the striker: [ame]https://www.youtube.com/watch?v=6vJQuxBVplY&t[/ame]

So I do exactly that, and wow the striker, firing pin, and striker channel were pretty dirty. Tons of gunk, debris, oil, and pieces of brass shavings everywhere. I cleaned up the striker and channel, using q tips and patches to get all the gunk and debris out. I also ran some Q tips covered with Breakthrough Military Grade Solvent to clean it, because in my experience it's really good at cleaning up gunk and I noticed that it dries completely after just 5-10 minutes which is nice. It fully evaporates and doesn't leave anything left behind. Everything I've read said to leave the striker and channel dry, never lubricate or oil it.

Below are some pictures of how dirty it was. I went through dozens and dozens of Q tips to fully clean the channel out. After I cleaned it, the white plastic and the silver striker and firing pin were nice and shiny. I haven't been able to shoot it yet after cleaning it since I literally just did this yesterday. Hopefully just a dirty striker was the cause of the light primer strikes and I don't get any more of those malfunctions next time.

After cleaning and putting everything back together, I tried to re-create the slide popping out of battery when smacking a mag in, and I couldn't re-create the issue. So it seems fixed for now. I'm still not sure why or if a dirty striker would cause such a thing, or if it's a separate issue entirely, so I'm going to keep an eye on it in case it happens again.

I also decided I'm going to start cleaning the striker and channel as part of my normal cleaning routine. I never knew it was this easy to do until now.


Video of my dirty striker: [ame]https://www.youtube.com/watch?v=exzcKpKXDiE[/ame]

Pictures:
https://imgur.com/qGjjob0

https://imgur.com/if5aZvo

https://imgur.com/jSpf7bZ

https://imgur.com/daJGcxK

 

[Real Old Navy]

Let us know if this corrected the problem.

 

[Ziggy2525]

You may want to pay extra attention when you're cleaning the pistol to see if there's something about your cleaning process that's letting oil seep into the striker channel. Things like CLP inadvertently spraying into the firing pin port or if you're lubing the rail slots on the slide having lub seep in around the striker block.

Just a thought.

 

[Real Old Navy]

You may want to pay extra attention when you're cleaning the pistol to see if there's something about your cleaning process that's letting oil seep into the striker channel. Things like CLP inadvertently spraying into the firing pin port or if you're lubing the rail slots on the slide having lub seep in around the striker block.

Just a thought.

Yeah combination of that and using ammo that burns dirty.

 

[WR Moore]

I've got a lot more rounds through a 1.0 and have never had anywhere near that much debris in the striker channel. I'm not sure what ammo you're shooting but the amount of brass particles suggest some issue with brass shaving.

Your pictures do show the need for periodic proper cleaning.

BTW, a good whack on the bottom of the magazine really isn't necessary and it isn't good practice as your standard loading method.

 

[jawman]

I never oiled or cleaned the striker, and knew to keep oil off the firing pin hole area. I'm wondering if I over lubed my Shield and oil eventually seeped in. I only oil the 7 spots per the recommendation in the manual, but I was putting extra oil all over the outside of the barrel. Also I was re-applying oil about once a month since I carry the gun and it seemed like it was drying out. Maybe it eventually was just too much oil and it eventually seeped in to the striker? I don't know. Or maybe since the shield is such a small gun with tighter tolerances, the striker assembly needs to be cleaned more often. I will report back to this post with an update if the light primer issues are fixed after my next range session.

 

[swsig]

I never oiled or cleaned the striker, and knew to keep oil off the firing pin hole area. I'm wondering if I over lubed my Shield and oil eventually seeped in. I only oil the 7 spots per the recommendation in the manual, but I was putting extra oil all over the outside of the barrel. Also I was re-applying oil about once a month since I carry the gun and it seemed like it was drying out. Maybe it eventually was just too much oil and it eventually seeped in to the striker? I don't know. Or maybe since the shield is such a small gun with tighter tolerances, the striker assembly needs to be cleaned more often. I will report back to this post with an update if the light primer issues are fixed after my next range session.

That's a reason to use grease instead of oil. It doesn't migrate, and it doesn't dry out. I use SLIP 2000 Extreme Weapon Grease, but any quality gun grease will do. Just don't use too much. A tube of SLIP will last a long time.

 

[jawman]

UPDATE!!: I took a pistol class this weekend, and right at the start of the class I was having the same issues again. The gun would fire once or twice, then I'd get a dead trigger or a light primer strike. I couldn't even get through half a magazine. Not wanting to miss out on valuable class time, I didn't bother trying to toy around with my Shield and instead chose to immediately switch to a backup gun that luckily was available, and I used it for the rest of the class.

After the class was over, I remembered that I had a new recoil spring assembly/guide rod in my range bag that was sent to me from S&W. I installed the new spring assembly and the instructor let me go back on to the range to see if that fixed the issue. I fired 3 magazines (24 rounds) rapid fire without any problems, which I thought was a good sign considering that earlier in the day I couldn't even get through a single magazine, as I was having problems after just one or two rounds. Unfortunately since the class was already over, I didn't have the chance to shoot more rounds with the new spring to see if that really was the fix, so next range trip I'll give it a full test.

My question is, could the guide rod/recoil spring assembly simply be the cause of the problems? When I purchased this v1.0 Shield 3 years ago, the shop I purchased it from has a certified S&W armorer, and he installed the Apex trigger and DCAEK kit on the brand new Shield. It went on to pump out thousands of rounds over the last 3 years without any problems whatsoever, so I didn't think that having the APEX trigger and DCAEK was the issue since it worked fine for so long. However, lately I was starting to believe that maybe the Apex parts were having the issues and that I should have just left the gun stock...

I'm glad I was able to get some positive feedback in the right direction after putting in the new spring assembly, and able to at least get through 3 mags without error. Next range trip will be the true test, but could the fix really be this easy, simply take out the original guide rod/RSA and replace with a new one? Are they known to cause these types of problems? Or were those 3 mags without issue a fluke? I know I won't truly know until I can get to the range and put a high volume of rounds through it, but just wondering if these types of problems can be caused by a bad guide rod/recoil spring.

 

[jawman]

Update: So I called Apex and told them what was happening, and the Apex rep walked me through a list of things to troubleshoot together over the phone. Everything was good until we got to the last thing on the list, and we determined that it is the trigger having too much overtravel.

So I took this information that I got from the Apex rep to my trusty gunsmith, and he confirmed that yup, there was too much overtravel, and that the trigger bar loop simply needed to be adjusted. Basically what was happening, was that occasionally during the force of recoil when firing live rounds, the trigger wouldn't reset, which is why I was getting a dead trigger, and explains why I never had any problems when doing dry fire practicing. He literally fixed it in 2 minutes, and then we shot 500 rounds without a single malfunction! So great news on that. Although I felt kind of silly with how EASY of a fix it was. If I knew it was that easy I would've just done it myself.

He also said that whoever installed the Apex kit for me didn't know what they were doing.

Also while the gun was with my gunsmith, he did a full on polish and custom fit job. He took everything apart, inspected it, and polished all of the moving parts, got rid of any burrs and rough areas, etc. They have a beautiful mirror shine finish to them now. And let me tell you, WOW! This thing is smooth as BUTTER! Soooo smooth and nice now, and the trigger reset is incredible. It really is something amazing. Now if only S&W sold their guns like this direct from the factory!

Anyway, I just wanted to update my thread in case anyone else has similar issues. It turned out to be a super easy fix!