Bolt assembly gas ring reliability issues - SIG Talk
SIG Talk Gun Forum

Bolt assembly gas ring reliability issues

This is a discussion on Bolt assembly gas ring reliability issues within the SIG Sauer Rifles forums, part of the SIG Sauer Forum category; Hey all, I just bought an M400 about 3 weeks ago. I took it home, stripped it, and cleaned off the factory lube and replaced ...


Go Back   SIG Talk > SIG Sauer Forum > SIG Sauer Rifles


SIG Sauer Rifles SIG Sauer Rifle Forum: SIG Sauer Rifles - SIG50, SIG516, SIG522, SIG551, SIG556, SIG716, M400, Blaser, SSG 3000, MCX, MPX

Like Tree12Likes
Reply
 
LinkBack Thread Tools Display Modes
Old 04-08-2017, 07:31 PM   #1
Junior Member
 
Join Date: Apr 2017
Location: ND
Posts: 6
Bolt assembly gas ring reliability issues

Hey all,

I just bought an M400 about 3 weeks ago. I took it home, stripped it, and cleaned off the factory lube and replaced it with my own CLP. I took it to the range today and fired about 250 rounds, no mag dumps, or anything strenuous. The gun ran great all throughout. When I took it apart later to clean it, I noticed a large gap in the gas rings on the bolt assembly, and realized it was indeed blown apart slightly. I didn't find any splintering or anything crazy, and the barrel is fine.
My question is; is it common that these gas rings on a brand new AR to fail so quickly? Does this stem from a deeper issue? I called my gun shop and asked them if this is common, and they said it is, but I am military, and these rifles that we shoot are abused and have had many many rounds through them and I've never seen these gas rings break before.
Theiceguy is offline  
Register

Welcome to the SIG Talk Forum dedicated to SIG Sauer Pistols and SIG Sauer Rifles.

We welcome everyone and the community is free to join so register today and become part of the SIG Talk Forum!

Old 04-08-2017, 07:45 PM   #2
Junior Member
 
Join Date: Apr 2017
Location: ND
Posts: 6
Here is a picture
Attached Images
File Type: jpg IMG_20170408_224439_1491709542008.jpg (2.02 MB, 74 views)
Theiceguy is offline  
Old 04-08-2017, 08:14 PM   #3
Senior Member
 
7.62Kolectr's Avatar
 
Join Date: Feb 2016
Location: on guard......
Posts: 2,639
There is supposed to be a small gap in each one. And they are supppsed to be offset so all three gaps aren't lined up. One of yours looks like it's missing a piece? Maybe Sig used some cheap subcontractor to supply them? Good thing is they are cheap and easy to replace. The rest of the bolt looks fine.
7.62Kolectr is online now  
 
Old 04-08-2017, 09:15 PM   #4
Senior Member
 
Join Date: Sep 2013
Location: Oklahoma
Posts: 1,304
It definitely looks like one of the rings is broken. Are there wear marks on the bolt, and is the costing uneven on the bolt? The tail and mid area near the ejector looks shiny.
jtallen83 likes this.
xrlizard is offline  
Old 04-08-2017, 11:59 PM   #5
Senior Member
 
Mills's Avatar
 
Join Date: Dec 2016
Location: Lone Star State
Posts: 2,402
Welcome to the forum.
Mills is offline  
Old 04-09-2017, 06:35 AM   #6
Senior Member
 
jtallen83's Avatar
 
Join Date: Jun 2013
Location: Iowa is home but I'm always travelling
Posts: 1,413
Quote:
Originally Posted by xrlizard View Post
It definitely looks like one of the rings is broken. Are there wear marks on the bolt, and is the costing uneven on the bolt? The tail and mid area near the ejector looks shiny.
That uneven wear would be my concern as well. Possibly the missing chunk of ring was jammed in there for a period causing the wear but it may be a machining tolerance issue. For replacement rings I would recomend the McFarland style;
JP Enterprises Enhanced One-Piece Gas Ring - .223 JPEGR-223
jtallen83 is offline  
Old 04-09-2017, 08:33 AM   #7
Senior Member
 
Willard's Avatar
 
Join Date: Apr 2016
Location: Evansville, IN
Posts: 2,081
Obvious, and as has been mentioned, you have a choice. First we need to find out why!
As mentioned it could have been defective parts, or the could be a problem in the bolt carriers bore, that caused possibly 2 rings to break...

If possible take a picture from the front of the carrier, into the bore, with the bolt removed, and a small flashlight shining through the rear of the carrier into the bore.
Post it, unless you see a physical flaw. If there was a machining problem, you need to let Sig fix it. If it is simply a gas ring problem, you should let Sig know. Replacing the rings with aftermarket parts, may fix the problem, but could also void the warranty if something else occurs.

It's up to you, also here are what the original gas rings look like, and the 1 piece replacement ring, as mentioned.
Attached Images
File Type: jpg KIT-GAS-RINGS.jpg (65.8 KB, 15 views)
File Type: jpg one piece gas ring.jpg (81.6 KB, 15 views)
xrlizard and kansascity45 like this.
Willard is online now  
Old 04-09-2017, 09:36 AM   #8
Supporting Member
Supporting Member
 
animalhd1's Avatar
 
Join Date: Dec 2012
Location: The Hollar
Posts: 1,080
I agree with Willard. I would suspect a problem inside the carrier bore that caused that. Gas rings should last for thousands of rounds.
xrlizard likes this.
animalhd1 is offline  
Old 04-09-2017, 10:09 AM   #9
Junior Member
 
Join Date: Apr 2017
Location: ND
Posts: 6
Hey everyone. Thank you for the replies! I am going to take the bolt assembly to the gun shop tomorrow and possibly call Sig and see what's going on with it. Here are some close up pics of it. Let me know what you think
Attached Images
File Type: jpg IMG_20170409_130805_1491761302410.jpg (1.56 MB, 30 views)
File Type: jpg IMG_20170409_130744_1491761312361.jpg (1.48 MB, 38 views)
File Type: jpg IMG_20170409_130652_1491761325373.jpg (3.02 MB, 34 views)
Theiceguy is offline  
Old 04-09-2017, 11:58 AM   #10
Senior Member
 
Join Date: Sep 2013
Location: Oklahoma
Posts: 1,304
Thanks for adding the pics, however, I cannot tell anything from the view inside the bolt carrier, but I agree with Willard and animalhd1, most likely you have some issue with the bolt carrier being out of spec internally. It could be failing rings, but as they said, these normally last a long time before needing replacement.

Here's a shot of mine from my 516.



The pic is kind of dark, but there is very little wear on it, and the tail has the coating just like the rest of the bolt. The shiny appearance of the tail is very odd, but at the same time, I don't really see how that would have an impact on the rings. Hopefully Sig can send you a new BCG for the gun, without requiring you send the gun in.
xrlizard is offline  
Old 04-09-2017, 12:43 PM   #11
Supporting Member
Supporting Member
 
animalhd1's Avatar
 
Join Date: Dec 2012
Location: The Hollar
Posts: 1,080
Quote:
Originally Posted by xrlizard View Post
Thanks for adding the pics, however, I cannot tell anything from the view inside the bolt carrier, but I agree with Willard and animalhd1, most likely you have some issue with the bolt carrier being out of spec internally. It could be failing rings, but as they said, these normally last a long time before needing replacement.

Here's a shot of mine from my 516.



The pic is kind of dark, but there is very little wear on it, and the tail has the coating just like the rest of the bolt. The shiny appearance of the tail is very odd, but at the same time, I don't really see how that would have an impact on the rings. Hopefully Sig can send you a new BCG for the gun, without requiring you send the gun in.
That shiny appearance on his bolt tail is probably from cleaning the carbon off. The 516 will never get carbon in that area because it's piston driven. The gas rings actually do nothing on a 516 and aren't even needed. In this case under warranty I would call Sig and get them to email you a shipping label and RMR to send the entire bolt carrier group back for them to inspect and replace if necessary.
xrlizard likes this.
animalhd1 is offline  
Old 04-09-2017, 12:48 PM   #12
Senior Member
 
Join Date: Sep 2013
Location: Oklahoma
Posts: 1,304
Bolt assembly gas ring reliability issues

Quote:
Originally Posted by animalhd1 View Post
That shiny appearance on his bolt tail is probably from cleaning the carbon off. The 516 will never get carbon in that area because it's piston driven. The gas rings actually do nothing on a 516 and aren't even needed. In this case under warranty I would call Sig and get them to email you a shipping label and RMR to send the entire bolt carrier group back for them to inspect and replace if necessary.


Good point on the appearance on the tail, and on the rings being unneeded on the 516. I've read where one forum member who is a gunsmith (can't remember his nic), recommends removing them on the 516 to reduce unnecessary friction, although I decided not to do try it on mine.

Last edited by xrlizard; 04-09-2017 at 01:24 PM.
xrlizard is offline  
Old 04-09-2017, 05:54 PM   #13
Senior Member
 
Willard's Avatar
 
Join Date: Apr 2016
Location: Evansville, IN
Posts: 2,081
Guys OP stated this is a M400, and not a 516, it's gas impingement, not piston, that's why there is carbon residue. That is carbon on the "tail" of the bolt. Theiceguy your pictures all appear to be of the bolt, and not of the inside of the carrier. That is what we need to see, as that is where the bolt and "rings" rides.
Attached Images
File Type: jpg Bolt Carrier.jpg (831.1 KB, 19 views)
Willard is online now  
Old 04-09-2017, 06:28 PM   #14
Senior Member
 
7.62Kolectr's Avatar
 
Join Date: Feb 2016
Location: on guard......
Posts: 2,639
In the rare off chance that the gaps on all three rings were lined up to create a single straight one instead of three offset it could have a created this. Almost every manual from every maker at some point has a 'warning' in it to make sure the gaps are offset. This is probably the reason for it.
Instead of the excess gas snaking its way thru three gaps offset it may have gone straight thru all three and caused that ring to break. Other than that I'll go with my first post, cheap or faulty ring and it failed. Very uncommon problem. I'd replace the rings and carry on.
animalhd1 likes this.
7.62Kolectr is online now  
Old 04-09-2017, 06:48 PM   #15
Junior Member
 
Join Date: Apr 2017
Location: ND
Posts: 6
Hey all.

I cleaned the bolt carrier group pretty well and didn't find anything out of the ordinary. I am going to take it tomorrow to the gun shop and see if they have any input on it. I'll keep you posted on it and update once I get some kind of word.
Willard likes this.
Theiceguy is offline  
Reply

  SIG Talk > SIG Sauer Forum > SIG Sauer Rifles

Thread Tools
Display Modes


Similar SIG Talk Discussions
Thread Thread Starter Forum Replies Last Post
MCX with New Carriage Assembly Finally Passes!! kansascity45 SIG Sauer Rifles 20 03-31-2017 05:49 PM
MCX Bolt Carrier Assembly - New Part Numbers kennethk SIG Sauer Rifles 0 02-25-2017 05:19 AM
How many rounds between cleanings before reliability issues Mainer 1911 Pistols 52 10-06-2016 06:20 PM


Top Gun Sites Top Sites List

Powered by vBulletin 3.8.7
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.6.1
Copyright © 2010 - 2017 SIG Talk. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.SIG Talk is a SIG Sauer Firearms enthusiast's forum, but it is in no way affiliated with, nor does it represent SIG Sauer, Inc. of Exeter, NH.