M&P Shield 9mm Light Primer Strikes

[BJLBJLBJL]

Hello all,

I'm hoping someone can give me some advice on an issue with my brand new M&P Shied 9mm. I bought it 3 days ago and have put 400 rounds through it so far. It's been flawless, with the the exception of 3 light primer strikes. Each one occurred with a different type of ammo (Remington ball, Remington JHP, Federal JHP). The dents in the primers of the 3 rounds that failed to go off were almost, but not quite, as pronounced as the ones is the spent casings I compared them to. All 3 rounds went off on the second attempt.

3 such incidents in 400 rounds means a failure rate of 0.75%, which isn't the end of the world, but naturally, we would all like our guns to go bang every time they're supposed to. Any ideas on how to resolve this issue? Could I be doing something wrong? Any guidance would be most appreciated.

 

[Bayoutalker]

Were these the first rounds on a new mag? If so, how are you racking them in?

Cliff

 

[OldLawman]

Sometimes there is too much lube in the striker channel which slows or cushions the fall. Factory guns can be over-lubed out of the box.

 

[Rastoff]

I require 500 error free rounds, without cleaning, before I'll carry a particular gun. Even so, 500 is not statistically significantly more than 400. And, 3 in 400 is not statistically more significant than 1 in 500. Obviously 0 would be better.

So, is this a new gun or used? Are there any mods to it like an Apex kit?

 

[BJLBJLBJL]

Were these the first rounds on a new mag? If so, how are you racking them in?

Cliff

These instances all occurred around the middle of the magazine. I believe it occurred once with the 7 round mag and twice with the 8 round.

 

[BJLBJLBJL]

Sometimes there is too much lube in the striker channel which slows or cushions the fall. Factory guns can be over-lubed out of the box.

As I was cleaning the gun last night after the range, I removed the striker and ran a q-tip down the channel. There was a small amount of lube and residue present. It didn't seem like much, but I have never cleaned the striker channel on any of my other firearms so I don't really have anything to compare it to.

 

[BJLBJLBJL]

I require 500 error free rounds, without cleaning, before I'll carry a particular gun. Even so, 500 is not statistically significantly more than 400. And, 3 in 400 is not statistically more significant than 1 in 500. Obviously 0 would be better.

So, is this a new gun or used? Are there any mods to it like an Apex kit?

It's brand new, and aside from a Crimson Trace laser guard, it's completely stock.

 

[Bayoutalker]

These instances all occurred around the middle of the magazine. I believe it occurred once with the 7 round mag and twice with the 8 round.

Wow, not much to go on. Everything was different except the gun itself. I'd suggest giving it another good cleaning and try again. If it still does it, might be time for a call to S&W.

Cliff

 

[much ado]

Shield Mis-Fire

I bought a new 40 Shield several years back and had similar problems,although to a greater extent. Mine even failed to fire on the very first round attempted. It took 3 trips to S&W...first time I don`t know what they did, 2nd time polished the chamber , 3rd time replaced the slide and barrel and voila! it worked 100%. S&W supplied shipping all 3X, got to know the local FedEx shipper. In retrospect and completely guessing, I would say that it did not return to battery "enough" to fire the effected rounds although from outward appearance it was locked and the striker did make contact.

 

[BJLBJLBJL]

I bought a new 40 Shield several years back and had similar problems,although to a greater extent. Mine even failed to fire on the very first round attempted. It took 3 trips to S&W...first time I don`t know what they did, 2nd time polished the chamber , 3rd time replaced the slide and barrel and voila! it worked 100%. S&W supplied shipping all 3X, got to know the local FedEx shipper. In retrospect and completely guessing, I would say that it did not return to battery "enough" to fire the effected rounds although from outward appearance it was locked and the striker did make contact.

Interesting. It didn't occur to me to check if it went fully back into battery. If it happens again, I'll make a note of it.

 

[Rastoff]

...I would say that it did not return to battery "enough" to fire the effected rounds although from outward appearance it was locked and the striker did make contact.

If it was in battery enough to release the striker, it was enough to fire the round.

As I was cleaning the gun last night after the range, I removed the striker and ran a q-tip down the channel. There was a small amount of lube and residue present.

This should not be a problem, but it doesn't hurt to clean it out.

Look closely at the striker. Is it bent?

 

[BJLBJLBJL]

If it was in battery enough to release the striker, it was enough to fire the round.

This should not be a problem, but it doesn't hurt to clean it out.

Look closely at the striker. Is it bent?

So, I gave my Shield a very thorough cleaning, including the striker channel. There was a little bit of gunk on the the q-tip that I used, but not very much. I took a good look at the striker and it appears to be perfectly straight. Lubed it up with some gun grease instead of the Hoppe's oil I had been using. Put it back together and made another trip to the range today. I put another 200 rounds through it and luckily no light primer strikes or malfunctions of any kind. It ran flawlessly. Not sure if it was cleaning the striker channel, or using grease instead of oil, or if it just needed those first 400 rounds to get smoothed out, but I was very happy about the flawless performance today. Hopefully, it will continue to perform like it did today from here on.

 

[Rastoff]

Lubed it up with some gun grease instead of the Hoppe's oil I had been using.

I'm glad it worked well, but I hope this means you lubed the slide contact points and not the striker. The striker and striker channel should be completely dry, no lube of any kind goes in there.

Lube in the striker channel will attract dirt and that will cause light strikes. It doesn't need any lube in there.

 

[Bonephish]

I'm glad it worked well, but I hope this means you lubed the slide contact points and not the striker. The striker and striker channel should be completely dry, no lube of any kind goes in there.

Lube in the striker channel will attract dirt and that will cause light strikes. It doesn't need any lube in there.

^THIS!^ And don't grease the sear, either.

 

[BJLBJLBJL]

^THIS!^ And don't grease the sear, either.

Ah. Yes. Let me be clear. I did not lube the striker or striker channel. I made sure that both were clean and dry. I only lubed up the 7 points on the Shield that need it.

 

[pyro]

I am glad it worked out for you. I had a Ruger sr40c that had a problem with light primer strikes and I sent it back to Ruger . I got it back and it continued to have the same problem. I sent it back a second time and when they sent it back with all new internals, I didn't even test it, I traded it in. It is unacceptable to have a gun with that problem. I would still be wary. Make sure you get a few hundred rounds through it for peace of mind.

 

[shawn mccarver]

3 such incidents in 400 rounds means a failure rate of 0.75%, which isn't the end of the world,

I must respectfully disagree. There should be NO failures to fire. Period. Barring bad ammo, which is almost certainly not the case here, based upon the facts you have related, a self-defense pistol (or any other kind) should go bang when you pull the trigger.

Either get it back to S&W to be repaired or get rid of it. The problem when you get it back is deciding how many rounds it will take to restore your confidence in the pistol. For me, it would be cost prohibitive to fire the pistol enough to convince me.

There is no excuse for a pistol that will not fire. I would get rid of it because I doubt my confidence would ever be restored unless the cause is determined with certainty and it is repaired. Headspace problem perhaps?

 

[Rastoff]

I agree shawn mccarver, but what is an acceptable failure rate to you? No mechanical device is 100% perfect. All will have a failure eventually. Above I stated that I expect a gun to go 500 rounds without being cleaned and without a single failure. What's your criteria?

The scary part is that most who carry a gun for self-defense don't put 400 rounds through their gun in their lifetime.

 

[Bayoutalker]

It doesn't matter where you set the level, the next shot could be a dud.

Cliff

 

[petepeterson]

If it was in battery enough to release the striker, it was enough to fire the round.

I didn't find this to be true with my ladyfriend's Shield. If it was slightly out of battery, it would dent the primer, but not fire.

I was involved in a few threads a few years back, but finally gave up when everyone was telling me why I was wrong. As I didn't own one, I didn't care enough to argue. We did put about 800 rds through it, and this was consistently the case, and was a result of her grip.