View Full Version : Seeking assistance with Sig Sauer M400 malfunction
I experienced a malfunction with my Sig Sauer M400. Other than some Magpul furniture and a Burris optic, the upper and lower (internals) are all stock.
Once I was able to get the bolt to release (it would not lock and it took a little (careful) prying to get it to ease out of the chamber. Once I could see into the breach, I discovered that a small "nut" (for lack of a better word) inside the breach cavity had worked its way loose. As the picture shows, its in the space between the bolt lugs and the bore.
The 'nut' was inside the breach and the bolt lugs had wedged up against it which caused the action to sieze up. There also seems to be a small gouge in the upper where the charging handle rides. My guess is it tried to migrate out of the action but was caught by the bolt before it could escape out the ejection port. Please see the attached picture. my apologies for the poor quality. auto focus wouldn't' cooperate with me and let me 'focus' on the hole - it kept picking up the edges of the upper...
I haven't seen this "nut" before but I only have 2 other AR uppers to compare with. The nut is VERY small and doesn't even have any discernible way to install it. IE: No cross-tip for a Phillips screwdriver or hex-head for an allen-stock.
I plan on calling Sig Sauer to discuss this, but I would like to have some background info on "what" this is.
Any info you guys can give me would be great!
thank you!
chasetopher
01-24-13, 21:47
Take a quick look at the bolt carrier key's fasteners, on the potential of there only being one intact.
Hidden inside, just aft of the chamber, is a protrusion that lines up with the extractor when the bolt is in battery. This button-like addition supports the extractor body when the gun is fired. Only 1⁄3 of an AR’s extractor is contained within the barrel extension when the bolt is fully in battery, leaving the remaining length retained only by the extractor pin that also acts as a hinge for normal function.
http://i.imgur.com/JrgkvqM.jpg
It looks like this part broke off or worked free.
Link (http://www.shootingillustrated.com/index.php/20746/sig-sauer-m400-2/)
http://i.imgur.com/JrgkvqM.jpg
It looks like this part broke off or worked free.
Link (http://www.shootingillustrated.com/index.php/20746/sig-sauer-m400-2/)
Yes sir, I do believe this would be the culprit. I can't see in the hole very well to tell how much is left in it. There are about 4 threads on the small, and by small I mean TINY piece that came out. I don't see any sign of any lock-tite on what threads are left......
Not trying to kick you when you're down, but this may be an example of a solution looking for a "problem." I was curious as to what Sig mean in their adverts by "supported extractor."
Thanks for the pics.
chasetopher
01-24-13, 22:11
I learned something new today, I was under the assumption that the m400 was only different from a standard AR with the lower receiver 'additions'.
It will be interesting to see what they have to say about this.
Heard somebody say something one that started with "If it ain't broke......"
but in all seriousness. The lack of Loctite has me concerned. I'm sure they have the "tool" to install it and apply some amount of torque to it. Given everything that's going on there, why wouldn't' they secure it better?
It's possible I'm the only guy this has happened to, but I have to doubt it..... Even though I think I have the worse luck of any human still living.
What if there was an overpressure problem from a bad cartridge and it saved you from completely destroying your rifle? What if it just accomplished its job?
Good point....
I'll give Sig a call in the morning and let you guys know what they say....
Thank you to b225 for pointing me in the right direction. My Interwebs searches weren't uncovering very much.
Thanks again!
I have no doubt that sig will fix the problem. I am curious though to see how long it takes. Can you keep us informed. I've always had issues with the time it took them to get my pistols bCk from them. Just chalked it up to less manpower.
Yes plus keep us informed. I have a Sig M400 as well and I haven't experienced any problems with it, but I would like to know how Sig handles your issue so that I can get an idea of how they'd handle mine if something were to happen. Thanks.
Update: Talked to SIG today and the customer service agent is sending me the RMA information. I was instructed to remove all after market parts. Just to be clear, I stated that I installed some Magpul furniture and needed to know if that needed to be replaced with the stock furniture. As expected, he said yes.
He also said, that there are many detents that could be displaced and that this device falling out was more than likely caused by my replacing the stock furniture. "I should be mindful of that when I get the rifle back that the same thing could happen again."
I'm taking that with a grain of salt. Seems to be a very canned response in light of what actually failed on the firearm. Seems to me the concern should be on the use of reloaded/remanufactured ammo rather than a replacement of a butt stock, pistol grip, and forearm. It is what it is....
As for how long this will take, his initial quote is 3 weeks from the time they receive it.
Update: Talked to SIG today and the customer service agent is sending me the RMA information. I was instructed to remove all after market parts. Just to be clear, I stated that I installed some Magpul furniture and needed to know if that needed to be replaced with the stock furniture. As expected, he said yes.
He also said, that there are many detents that could be displaced and that this device falling out was more than likely caused by my replacing the stock furniture. "I should be mindful of that when I get the rifle back that the same thing could happen again."
I'm taking that with a grain of salt. Seems to be a very canned response in light of what actually failed on the firearm. Seems to me the concern should be on the use of reloaded/remanufactured ammo rather than a replacement of a butt stock, pistol grip, and forearm. It is what it is....
As for how long this will take, his initial quote is 3 weeks from the time they receive it.
Hmmmm... that's discouraging... With all the things I've changed out on my M400, it would be a major pain in the ass to change it all back out if I had to send it in... Glad I never broke that castle nut to put that DD QD plate on... It's kind of ridiculous to imply that changing out a buttstock, pistol grip, and forerarm could cause such a thing to happen...
Update: Talked to SIG today and the customer service agent is sending me the RMA information. I was instructed to remove all after market parts. Just to be clear, I stated that I installed some Magpul furniture and needed to know if that needed to be replaced with the stock furniture. As expected, he said yes.
He also said, that there are many detents that could be displaced and that this device falling out was more than likely caused by my replacing the stock furniture. "I should be mindful of that when I get the rifle back that the same thing could happen again."
I'm taking that with a grain of salt. Seems to be a very canned response in light of what actually failed on the firearm. Seems to me the concern should be on the use of reloaded/remanufactured ammo rather than a replacement of a butt stock, pistol grip, and forearm. It is what it is....
As for how long this will take, his initial quote is 3 weeks from the time they receive it.
That is BS. This is a QC / design problem and has nothing to do with what aftermarket parts you installed. I wasn't aware of this" feature" on the M400. Solution looking for a problem, as you have unfortunately discovered. Sorry for your trouble man.
Their request to remove aftermarket parts is likely to reduce hassle on their end when performing warranty work. If you send them a stock upper, they can just replace it with another and not have to be responsible for your parts.
Like the op said. Sounds like a canned response. Most manufactuers prefer that you remove any non factory installed parts. Nothing to be shocked about.
Sig has always been good to me. I just hated their turn around time, although three weeks sounds reasonable to me.
texasgunhand
02-07-13, 19:59
I cant see how on earth changing the foregrip could poss. be at fault for this coming loose.
please update when you find something out for sure.very interresting though.i just popped mine apart and it looks like its cast into the barrel, i also wonder if you had an over-pressure? did you take any close ups of the part that came loose?? I would be interrested in seeing them if you did.. iam sure sig will fix it for you anyways...
I had some things come up which delayed me making the trek to my FEDEX Hub to get the M400 mailed back. Anyway, it arrived at Sig on the 5th. So far, no news from them - which isn't surprising since it's only been a couple of days.
@Texasgunhand: I don't have a very good camera so I can't get a great closeup of this thing. not to mention, I packaged it with the M400 for the return along with my note to the gunsmith on what I was doing/what ammo I was shooting etc. Anyway, there were threads on the shank. As if this thing were screwed in. VERY fine threads to be sure. The more threads there are, the more secure it should be right? What I didn't see was any kind of residue, from a compound like Loctite. Again, I'm not sure that this was all of that device - my eyes aren't the greatest and even with the magnifying glass it's hard to see if it looks broken. The thing got bounced around I my upper like a pinball machine before it finally got wedged in the bolt battery by the bolt.
As for overpressure, I do a little reloading, so I save all my brass. The rounds I put through the M400 have all been factory up to this point. Mostly, because I don't want to shoot through all the rounds I've made just to break-in/sight-in this platform.
Anyway, back on track: I inspect all my cases before I process them, and I have processed all of the cases I shot that day - there weren't very many...... I have seen no indication of overpressure on any of the rounds I expended. No 'overly' bulged cases, no primers out of place. I also don't recall any particular shot 'feeling' any hotter than any other I've fired.
I think as a reloader, we tend to dial in to that perception a little more than normal. Or perhaps it's just me and i'm wasting time/energy doing it. Certainly we all want to know if we had a slow burner or a bullet not leave the barrel. So, anyway, even if I were shooting reloaded ammo (Yes, I know it voids the warranty) I never - EVER load hot. Let me repeat that - I never EVER load hot. It's a waste of powder for starters. Second, most of my logs show that the most accurate rounds aren't screamers and typically fall within the lower 1/3 of the loads min recommended powder charge (depending on the data). I measure powder throws QUITE often during the process. I also measure a healthy sampling of the bullets for uniform length (the projectile itself not just the C.O.A.L.) a longer bullet will have to seat further into a case to obtain the same C.O.A.L. Even companies like Sierra let a few get away from them that don't pass 100% QC.
I don't claim to load 'match' ammo, but if I'm going to shoot, I want it to be accurate. even if it is just a paper target.
Sorry for the novel. I hope Sig will make this right. I have faith that they will.
NeoNeanderthal
02-07-13, 21:04
Just took my armorers class at sig 2 months ago. They were very proud of said feature and stated that it was to support/contain the extractor in the event that the gun blew up. This would supposedly keep the extractor from flying out and "killing someone."
Just took my armorers class at sig 2 months ago. They were very proud of said feature and stated that it was to support/contain the extractor in the event that the gun blew up. This would supposedly keep the extractor from flying out and "killing someone."
Did they mention how that would happen? Like, what this thing does and how it defuses the energy? Going on the "in order for something to become clean something else must become dirty" theory.... They tell us consumers what it does, did they tell you folks who repair it - HOW it does it?
My Sig M400 was delivered to me this morning. According to all the tracking info, they received it on the 5th and it started its journey back to me on the 10th. FedEx acutally tried to deliver it yesterday but nobody was home to sign for it. Needless to say, I made sure I was there for it today :D
The documents inside state that the upper receiver, bolt, bolt carrier group, and the extractor support were all replaced. "2 magazines" of rounds were expended in test fire with no malfunction.
I'll be mounting my optics and replacing furniture tonight, and hopefully getting some range time this weekend.
I would like to add that I am MOST pleased with the AWESOME turn around time and no-hassle customer service up to this point.
I'm curious to know why they believe it failed. Did they give any insight?
No sir, no insight at all.
The packing slip that was enclosed described what was replaced and that they fired two magazines worth of test fires.
I do have a gunsmiths name, I wonder if it's worth the time to call and ask to speak with him and pick his brain.
.46caliber
02-14-13, 13:58
No sir, no insight at all.
The packing slip that was enclosed described what was replaced and that they fired two magazines worth of test fires.
I do have a gunsmiths name, I wonder if it's worth the time to call and ask to speak with him and pick his brain.
Can't hurt to try. I'm interested as well to know their thoughts.
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9 days is astounding... My guess would be that with all the M400s they've sold before and during the panic, that there must not be much of a waiting line if you got it back that quickly. I translate that as very good news as to the reliablity of the platform. They probably don't MP/HPT/whatever test that little set screw and you must have gotten the one out of however many with a hairline fracture or some other metallurgic inconsistency. Let us know if the issue arises again. I'm almost tempted to go poking around inside my Sig now to see if I can remove that sucker. But with my luck, the next time I'm at the range, I'll end up blowing the extractor out the side of my gun and killing the poor dude next to me. Then I'll be up shit's creek since I disabled a safety feature of the weapon...
texasgunhand
02-18-13, 01:16
Hey great that was fast, iam glad you got it back fixed and ready to go again.I looked online for anyone else posting this problem,and couldnt find it. just a fluke iam sure.Ive talked to sig a few times and they do shoot between 30 and 50 rounds before it leaves them.
i got mine out and looked at it and your right its hard to see..lol..
When i got my m-400 the mag was scratched "found out later it was test fitted at nhmg,and the molly coating scratches easy." anyway i ordered another mag from them and when i called they said there was a 4 month wait,but after talking to them the mag was on my door step in like 8 days. I havent got to shoot mine alot yet becouse of the crazyness right now,you cant even find .22 ammo right now ,i never thought i would see that!
Glad you got it back anyway good luck and have some fun...:dance3:
Someone in the thread said to stop by if this problem occurred again. It has.
I've been shooting a mix of .223 and 5.56 ammo for the past year. On my last outting, the gun jammed and I relived the nightmare of the last hard stoppage. Sure enough, the extractor support is no longer in the barrel extension. I looked around the area where I was shooting but couldn't find it.
Someone in the thread said to stop by if this problem occurred again. It has.
I've been shooting a mix of .223 and 5.56 ammo for the past year. On my last outting, the gun jammed and I relived the nightmare of the last hard stoppage. Sure enough, the extractor support is no longer in the barrel extension. I looked around the area where I was shooting but couldn't find it.
That should indicate to you that something is not right with that design feature. My advice to you is to dump your rifle and replace it now while the market is good.
.46caliber
10-11-14, 08:18
Someone in the thread said to stop by if this problem occurred again. It has.
I've been shooting a mix of .223 and 5.56 ammo for the past year. On my last outting, the gun jammed and I relived the nightmare of the last hard stoppage. Sure enough, the extractor support is no longer in the barrel extension. I looked around the area where I was shooting but couldn't find it.
What items were replaced on the work list? What ammo and mag were you shooting when the stoppage occurred? I assume the rifle continued to function after the stoppage occurred.
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Through the last year of shooting it I've used a wide assortment of ammo. The day this happened IWas running American Eagle 556 62grain through a Magpul mag.
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JBecker 72
10-11-14, 08:55
Sorry to hear. If it were me I'd have it fixed again and then dump that upper like a bad habit. Replace it with something quality like Colt or BCM.
With the exception of the gas key, I have not seen any thread locker or staking of M400 screws. I believe the extractor support screw (or whatever the part name is) can be removed. Double check with Sig.
The Sig M400 has some extra parts and gimmicks, but guns I see (~50) otherwise run well. If yours meets your needs otherwise, dumping it wouldn't be my first corrective action.
Also, you'll want to keep an eye on this one as well:
http://i76.photobucket.com/albums/j18/Skintop911/SIGARMS%20M400/SIGM40045.jpg
http://i76.photobucket.com/albums/j18/Skintop911/SIGARMS%20M400/SIGM40041.jpg
JBecker 72
10-11-14, 09:03
Is that a tensioning screw for the upper to lower receiver fitment?
.46caliber
10-11-14, 09:04
Did they reinstall the stud? Replace the barrel or extension.
The extractor support stud is the only thing really odd about the Sig M400s, and the problems have been very isolated at that. With it gone, the rifle should function like any other AR. And the small cavity in the extension should pose little problem other than maybe gunk collecting.
I'd either run it as is, re- barrel with BCM or DD or other quality, or sell it and replace with BCM or DD or other quality.
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.46caliber
10-11-14, 09:05
Is that a tensioning screw for the upper to lower receiver fitment?
Yes.
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texasgunhand
10-14-14, 12:25
Man that sucks so bad this seems to be the only problem iam hearing about with these rifles, i would just run it with out it. I cant see what it would hurt either..how are they installed? pressed in? Theres a link some were here about it happining in a 516 also so i dont think its limited to the m-400. I also think Grant said it has happened in the hk416 also,but could be wrong about that..
10mmSpringfield
10-14-14, 13:33
My Sig M400 was delivered to me this morning. According to all the tracking info, they received it on the 5th and it started its journey back to me on the 10th. FedEx acutally tried to deliver it yesterday but nobody was home to sign for it. Needless to say, I made sure I was there for it today :D
The documents inside state that the upper receiver, bolt, bolt carrier group, and the extractor support were all replaced. "2 magazines" of rounds were expended in test fire with no malfunction.
I'll be mounting my optics and replacing furniture tonight, and hopefully getting some range time this weekend.
I would like to add that I am MOST pleased with the AWESOME turn around time and no-hassle customer service up to this point.
Sig refilled the metal shavings that keep escaping and causing rifle malfunctions.
Remember to only use Sig approved accessories, that includes optics that say Sig Tac on them.
Researching the process to drop a new barrel into this upper, I think it would be easier to just get a whole new upper. I don't have the tools or experience.
While I'm willing to learn I don't want to cause more damage than I'm repairing. So perhaps just replacing the upper then learning on the old Sig upper would cause less hassle.
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Someone in the thread said to stop by if this problem occurred again. It has.
I've been shooting a mix of .223 and 5.56 ammo for the past year. On my last outting, the gun jammed and I relived the nightmare of the last hard stoppage. Sure enough, the extractor support is no longer in the barrel extension. I looked around the area where I was shooting but couldn't find it.
Am I right in assuming that your M400 is no longer under Sig factory warranty? If so, that sure does suck!
Haven't checked with them yet to he honest....
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Why replace the barrel/upper?
.46caliber
10-14-14, 16:57
Am I right in assuming that your M400 is no longer under Sig factory warranty? If so, that sure does suck!
Haven't checked with them yet to he honest....
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Sigs are limited lifetime, at least for original owner. I would bet if he sends it in they'll either install a new extractor support in the barrel extension, install a new extension or barrel or replace the upper, all with the support.
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I meant to call today but got busy with retirement out processing. Tomorrow should be better
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texasgunhand
10-15-14, 13:48
Does anyone know how the part is held in place? ie pinned,, pressed etc???
In a similar vein, I had a Sig 716 with a barrel extension that had such sharp feedramps that it would nearly slice through the case when fed.
I had a similar exchange with Sig Customer Service that firmly cemented my notion of never buying another Sig product. Their CS department is incredibly cavalier and should be gutted entirely.
The nerve of selling me a $2000 shitbox rifle and then accusing me of being inept when it was their inability to produce a quality product made me furious.
texasgunhand
10-27-14, 19:35
Will agree they are some smart butts,the mang.was nice.But the guys who answer the phones really need improvement.
Will agree they are some smart butts,the mang.was nice.But the guys who answer the phones really need improvement.
My only dealing with Sig CS went swimmingly. I couldn't have asked for a cooler guy on the phone. He didn't question me at all, could tell that I knew what I was talking about, was super-friendly and apologetic, and had a return label in my inbox moments after hanging up with him. The whole call couldn't have lasted more than a couple of minutes. (The gun I was having trouble with was a P238 with a sticky trigger).
EDIT: ...and to top it off I had my P238 back with a match-grade trigger in only 5 days after sending it out.
Exactly the same here, some time back. I talked to a very nice lady who could not have been more helpful. Shipped on their dime, and super fast turnaround. I know we've drifted slightly off topic, but this thread has evolved into a "will they take care of it" discussion.
Skip
I know that this is an old thread, but did they ever take care of your rifle the second time around? How is it running today?
I lost interest in it.
Tapped on my Samsung Galaxy S4
If you have an over pressure that is bad enough to bend the extractor, that button isn't goes to save you. The pressure will just find something else to break...
If you have an over pressure that is bad enough to bend the extractor, that button isn't goes to save you. The pressure will just find something else to break...
That's a little like saying that if you're tailgating someone on the freeway and they slam on their brakes, that you slamming on your brakes won't save you - while it probably won't help much, the tiniest amount of deceleration could mean the difference between a broken neck and whiplash. I applaud Sig for trying something out of the norm, and just like any innovation in its infancy, there will be growing pains. Once they get the kinks worked out, it could set a new standard and we could be seeing these little pins in every AR. Probably not, but just a thought.
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