First off, I want to start off by saying I just joined this forum a few minutes ago, so I have no idea if I'm doing it right. I bought a shield in 40 a month ago on my 21st birthday for concealed carry and love the gun, and am just starting to get familiar with it. The first thing I noticed after firing my gun many times (have put around 350 rounds through it) is that the dents in the primers are sometimes different looking. Most of the time the spent cases have a very good solid dent in the primers, but on the 6th or 7th shot usually the dent in the primer will be a very very shallow dent and not like the others from the previous shots. Sometimes I wonder how the round even went off it's so shallow. That being said though, I haven't had one miss fire from a light strike yet, but I am very concerned that it isn't supposed to be like that. So that's why I wanted to know if it was normal or not. I am also new to striker fired pistols, and pistols in general really. I have shot rifle/shotguns all my short life, but am just now getting into handguns. Another thing I wanted to ask is when I should clean the firing pen? it says in the manual not to take the gun down any further than it recommends so I don't know about that. You would think after so many rounds that you need to get in there and clean it right?

I think you are saying on your last couple shots to empty the mag/gun, you are getting strange primer indentation marks. That should not happen, they should be similar from start to finish, except as the gun gets lighter, you may be allowing more flip, which could cause this, but is not very likely. Try to maintain as little of flip as possible and see if there is any change. Since you may be having an issue, if you know how to remove the striker, check that it and the bore is clean. Do not lube it when you reinstall it. If you don't know how to get it out, search YouTube for M&P striker removal.

Maybe check it every 2000 rounds, but some have fired 10000 rounds and never removed the striker.

Bob

The marks you describe are normal. The breech face has a tear-drop mark below the firing pin hole and that is transferred to the primer when fired. You might consider cleaning your firing pin after you have fired 1000 rounds or so. If you are unsure how to do it find a local gunsmith to do it for you. Enjoy your new gun.

First of all, welcome to the forum.
I agree with what the above 2 posts say about the primer strikes.

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James
On the Llano Estacado

Worry about it when you start getting FTF. As long as the firearm is firing your good to go. Remember you have a warranty with your firearm but I under stand you may not want to send it in, but if it bothers you, you can give the mothership a call and they will want you to send it back. Maybe some pictures so we can see if there is anything you need to be told as were won't know how light the primer strikes are unless we can see them. All the strikes should be close to the same.

And a warm from “wild and wonderful “ West Virginia at least that’s what they tell us.

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Psalm 23:4

Welcome from North Carolina

Welcome from Texas!

This is what I was talking about.

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Just put the picture on here, hope I did it correctly, and thanks for the reply.

I'm from north Carolina too!

Thanks a lot. I was thinking the same thing. I posted a picture if you want to take a look at it. I started to think maybe that could be the problem because I like to fire the last couple of rounds quickly, and maybe my grip loses up a bit and that causes the slide not to go back all the way causing a tiny difference in the way the primers strike. I looked up on youtube how to get the firing pin out, it seems pretty simple. I just don't want to press that button and a part fly through the house lol

thanks, and I'm pretty sure I can do it, and if not I need to learn it anyways.

The photo shows the primer on the left with a more pronounced primer swipe (also called primer smear, primer wipe, and others). The primer on the right has a very small start of a primer swipe, a very shallow line. It is caused by the striker (or firing pin) remaining inserted into the primer when the chamber drops, during recoil. I will list then causes for striker fired pistol, but these causes would also include pistols with a firing pin.

Caused by: Weak striker return spring which does not allow the striker to retract fast enough; Weak recoil springs which allows the slide to recoil too fast, before the striker can retract; Dirty or sticking striker or striker bore, which slows the striker retracting speed. The striker tip causes the line in the primer as it drags across the primer, as the chamber drops. The line is thicker near the center and becomes thinner as the line moves away from the center, since the striker tip is retracting.

Some thoughts about swipes suggest that weak wristing and excess flip can cause the condition, but I am not convinced that is accurate. Weak wristing can slow the slide movement, which would actually reduce the chance for primer swipes, allowing the primer extra time to retract before the chamber drops. The only way weak wristing could cause primer swipes is if was slowing the striker retracting movement. The only way to test for sure would to shoot from a sandbag rest, making sure to eliminate most all flip, and then checking the primers.

Many pistols produce primer swipes and this is not anything to be concerned about. The pistols still function perfectly, but the primers will show the swipe markings.

Yes it is pretty easy to remove and reinstall the striker. The issue of primer swipes should be fairly consistent, meaning if you get them, all primers should look similar. Since you are getting differences, it would suggest something is changing during shooting. Again the swipes should not cause any function problems when shooting the gun, other than the look of the primers indentations.

Bob

Welcome from New Orleans.

And another welcome from Texas!

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Lounge Lizard Extraordinaire

The primers from my 40 Shield look just like that, I wouldn't worry about it.

ON EDIT: Welcome from Michigan, and congratulations on the new gun.

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John

I have a Shield 9mm and it has always had a strong slide and can be easy to limp wrist as well. I would think the 40 has some good kick so there is a good chance even with a strong shooter there is a little flip and could get more after a half dozen shots. If it is firing and you are hitting the target I would just keep shooting.

Check your ammo.

If an occasional primer is not seated completely it will absorb some of the striker impact.

Good Luck

Wow you explained that about as good as it can get. I will keep shooting and practice a stronger grip and see if that makes a difference. Generally, I hold with a very tight grip and stiffen my right arm completely, but still get a bit of muzzle flip. This will be fun practicing anyways because it gives me an excuse to put more rounds down range. Thank you for the response. I will also try the sand bags if it continues. I also will disassemble it and clean it up really good just for the fun of it.

Yeah the recoil's definitely there but it doesn't bother me at all. I guess I need to practice my grip though. After all this is basically my first pistol besides a 22lr and 38spl. I don't get To much muzzle flip when I'm shooting, but I'll work on it. Never hurts to practice.

Good point because it's wwb. I have also shot federal aluminum case, blazer, and same results. However I have shot some Hornady critical duty and didn't notice any shallow dents.

Yeah, I'm starting to think it's mostly normal and I need to practice my grip.

The difference in primer strike could be difference in the charge of each cartridge or how the powder is distributed inside the case just before firing. Both look like normal primer strikes.

welcome from Florida, that's normal, put the microscope away and enjoy your MP.

I've shot a lot of rounds through my 40 shield and honestly never looked that close at the casing. As long as it goes bang when I pull the trigger who really cares what the primer dent look likes.