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Discussion Starter #1
What cause an M&P to fire out of battery? What is not working properly? Where do I need to look?



Background: I thought I was having pressure problems with my ammo (9mm). Primers were not flattening but everynow and then I would get a case stuck in the chamber. The extractor would pull right off the rim. I had to use a squib rod to get one out Tuesday. The primer was fine but the case was buldged at the bottom with a signifcant edge along the unsupported part. Then, when I was picking up brass, I find the piece in the picture below. I don't remember shooting it (it fired and ejected but did not feel funny). So, I thought it was my ammo but then I was having problems with very light loaded ammo - getting stuck in the chmaber. I have been shooting the same ammo in my other M&P with out any problems. So, I showed the brass to some friends at the range today and everyone at the same time said - "It fired out of battery". So, what do I need to check/look for? Any feedback would be appreciated. Thanks.







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high primer, possibly.
 

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Are these reloads or factory rounds? Do you case gauge them all? Could have been a slight bulge in the case already that hindered it from chambering. More than likely though, it may have had a little to much powder in it!
 

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coltman1985 said:
Are these reloads or factory rounds? Do you case gauge them all? Could have been a slight bulge in the case already that hindered it from chambering. More than likely though, it may have had a little to much powder in it!


Man, that is not the result of a little too much powder. I would have to agree that that is the gun firing out of battery. In theory, it should not be able to do so (i.e. if a case fails to chamber, the gun should not set off the round).





To the OP, have you done a trigger job on the gun? If so, what did you do? Did you cut any coils form the firing pin safety spring?



Also check if anything is causing the firing pin safety to be jammed in the up position.





Whatever it is causing it, that gun is not safe at the moment.
 

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Can we get a good pic of the head stamp? That doesn't look like a out of battery that looks like a resizing mishap. I have never seen a case get expanded evenly the whole way around like the including the primer pocket and case rim.
 

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Dan Burwell said:
Can we get a good pic of the head stamp? That doesn't look like a out of battery that looks like a resizing mishap. I have never seen a case get expanded evenly the whole way around like the including the primer pocket and case rim.


I agree.
 

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Discussion Starter #8
Sorry for the delay in responding guys, I was at a football game yesterday. Anyway, here are the answers to the questions.



This was a reload though I have had factory rounds get stuck, too (Atlanta Arms, Winchester, and R&P). I Casepro all of my brass and use a Lee U-die on my 1050. I have case guaged all rounds and when I box them, I run a sharpie across the primers to make sure they are seated and to mark my brass. I am pretty sure it is not a primer problem. My load is 3.5 grns of Clays, 135 Grn Zero FMJ, OAL of 1.115. When fired, there are no classic pressure signs - primers are not flattened.



I have done a trigger per the online instructions that were posted here. I redeuced and polished the sear. Polished the contact surface of the striker. And rounded and polished the disconnector. I am beginning to think that I may be having a problem with the disconnector. Every now and then, when I rack the slide dry-firing, the slide will not go completely into battery. I notice this when I squeeze the trigger. The slide will actually move forward. So, I am going to take it down and see if I can tell what is going on. It does not seem like there is something restricting its movement.



Here is a pic of the headstamp...its Win brass from Winchester White Box 147s.

 

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Thanks for the pic. from the first ones it was hard to see that is was just one side bulged. There is something very wrong with your gun. it shouldn't be able to fire that far out of battery the slide should have disconnected the trigger and your FP stop plunger should not have been fully lifted yet. So the trigger bar shouldn't be making contact with the sear and even if it did the striker shouldn't be able to get past the plunger if it isn't lifted. Hard to say exactly where you problem lies without it in hand but I wouldn't doubt it if there is more than one issue here. Sorry not want you wanted to hear I know.



You can try dryfiring it out of battery and let us know how far you must retract the slide before it will not fire, maybe we can start there.



Just out of curoisty when you did the trigger job did you bend the ramp on the trigger bar at all (the part that interacts with the sear)? That could be allowing all of this to happen.
 

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Discussion Starter #10
Dan,



Thanks for the feedback. I dry-fired the pistol and discovered that I could get it to fire with the slide just at 3/16ths of an inch out of battery. So, I took the gun down this weekend and checked what I could. First thing I discoverd was that the striker was sticking a bit when forward. I found that the striker channel was full of very fine brass shavings. I checked some brass and it appears that the striker has been dragging on the primers a bit (not retracting fast enough?). So, I cleaned that out thoroughly. I also checked the striker safety plunger. It seemed to moved freely.



Next, I started thinking that the trigger bar was engaging the sear too soon - perhaps I did not remove enough material from the engagement surface of the sear. Since I bought a replacement sear block (in case I screwed the trigger job up), I decided to remove a little more material from the sear engagement surface. That seems to have been most of the problem. The pistol will not longer fire with the slide that far out of battery. It will allow me to fire it with the slide "barely" unlocked (I can't even get a measurement), so I figure a little polishing might address that?



Now, my question is what is causing the firing pin (striker) safety to rise when the pistol is still out of battery? What are the possibilities? 1. trash causing it to stick? I think I have fixed that by cleaning it thoroughly. 2. Some foreign material in between the slide and the frame that is disengaging the safety? I could find no evidence of that. 3. The trigger bar engaging the safety pre-maturally? Could it be that I did not round the striker safety enough? The way I see it, if I reduce the engagement surface of the sear, the trigger has to travel more distance to engage the sear. In doing so, isn't it engaging the firing pin safety sooner, unless the contact surfaces on the firing pin block have been reduced?



I fired it yesterday, shooting some fast bill drills and it seemed to run fine. No indication on the brass that it was even close to being out of battery. No buldges on the brass. I am guessing that I am close to resolving the issue. I'll keep an eye on it. I have the USPSA Nationals next week so I have to go with it. Thanks again for the feedback.
 

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I hope everything works out for you. That's a very strange deformity, though it looked far worse before you posted the last picture.



Good luck in IPSC.
 
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