View Full Version : Another SIG 556 problem discovered- Gas valve ports reversed
We all know about the numerous different types of QC problems documented about the Sig Sauer 556. Here is one I discovered while disassembling a 556 made in 2009, and I don't believe anyone else has brought it up before. I chose to post it here at M4carbine.net, since this forum's users take their weapons more seriously so to speak than forums whose member base consists mainly of casual/recreational shooters.
First, the function of the gas valve on the 550 series needs to be briefly explained. The valve has two positions, one for normal shooting and one for when the weapon is fouled (or frozen with ice) to the point of not cycling. This second position is also sometimes referred to as the "Emergency" setting, and lets much more gas in to act upon the piston to dislodge. The gas pressure in this position is so strong, the manual (Both US and Swiss) caution NOT to run the weapon in this position unless absolutely necessary due to the added stress on the parts.
From the Swiss manual:
http://i51.tinypic.com/wrewjb.jpg
The valve has two ports, the smaller one for the normal setting and the larger is obviously for the fouled/emergency setting. On both sides of the gas block, there are downward venting exhaust ports (Located between the roll pins) :
http://i52.tinypic.com/2s6m4bo.jpg
The smaller gas valve port is directly underneath and in line with the exterior rib, which during normal use is in the vertical 12 o'clock position. The smaller port lets in less gas from the barrel into the system, and at the same time the larger gas valve port will exhaust excess gas out of the left side of the weapon. Switch the rib to the emergency setting, and the larger port is now inline with the barrel. Obviously the larger hole lets in more gas, but the smaller port now does exhaust duty out the right side.
So its not just a matter of having small or large inlet ports to choose from for letting gas in from the barrel, but you also have a smaller and larger exhaust port as well. And the only choices of this combination are "Small intake, Large exhaust" or the brutal "Large intake, Small exhaust."
Here is a photo I saved that was posted about a year ago on another forum of a Swiss gas valve. I do not remember the poster's name, but if you are here shout out and I'll give you due credit. Notice the normal (Small) port on the left, larger on the right.
http://i54.tinypic.com/2udz1na.jpg
And here is what I found when I compared my own Swiss 551 valve (left) next to the US made 556 valve (on the right) :
http://i53.tinypic.com/2ynihif.jpg
http://i55.tinypic.com/2q3uj5l.jpg
I don't have access to any tools or even drill bits small enough to measure the port sizes. One person I showed the photo to thought it was somehow an optical illusion, so I verified the size difference with a sewing needle.
http://i56.tinypic.com/vi1rug.jpg
Obviously I think it would probably be a good idea for 556 owners to check their valve ports before the excess wear and tear of unknowingly shooting in the "Emergency" setting takes its toll.
Reagans Rascals
04-29-11, 04:29
Did you like the rifle when you fired it? Did you experience any malfunctions? I really like SIG and I appreciate your post, it has shown me a lot before a purchase, would you purchase it again knowing what you know now?
I can tell the port sizes are different in one of your photos so its not an optical illusion.
Dirtyboy333
04-29-11, 04:34
That's ridiculous that they can't even drill the right size ports in the right place.
I'm actually drilling new ports for mine on the flip side (see the 55x sticky at the top of this sub forum) and while researching the project I talked to a guy who has a bunch of extra valves laying around from conversions that he will sell.
He told me to contact him on Saturday to purchase and once I get the details on price etc. I'll let you know if your interested.
dwhitehorne
04-29-11, 16:12
Well that is interesting. I've got about 1800 rounds through mine without any issues. I'm going to have to go home and check to see. Other than cleaning it a couple of times, I have never really payed any attention to the valve. David
That's ridiculous that they can't even drill the right size ports in the right place.
I'm actually drilling new ports for mine on the flip side (see the 55x sticky at the top of this sub forum) and while researching the project I talked to a guy who has a bunch of extra valves laying around from conversions that he will sell.
He told me to contact him on Saturday to purchase and once I get the details on price etc. I'll let you know if your interested.
Wouldn't it be much, much easier to simply order a correct Swiss made one?
Moose-Knuckle
04-29-11, 18:18
SO thankful I sold my 556 off and got what I had into it! :eek:
variablebinary
04-29-11, 19:02
Not surprising.
If SIG USA can't get the big simple things right (rail alignment, finish, proper fitting furniture), then there is no way in hell the little, vitally important details & things are done right.
Dirtyboy333
04-29-11, 20:30
Wouldn't it be much, much easier to simply order a correct Swiss made one?
Yes that would be much easier........BUT i don't know where to get them. CO Arms sells the whole piston system but its so damn expensive and im not really worried about converting my 556 into a 551 or such. I would like to, but weighing the cost/benefit for my needs its not nearly worth it.
Why, do you know of some that are for sale? That would be great!!!
Also, theres a couple of pics floating around of the regulator from a STGW90 (i think) and the GP's on it were slightly larger than mine. I want to be smaller.
ETA: The pictures i mentioned are in this original post :sarcastic: but ive seen it other places prior to this
Thank you for posting this...seems like this would've been brought to Sig's attention. Have you shown this to them? Have they responded? Seems like a recall issue.
Thanks again!
PS - Go Steelers!
RogerinTPA
04-29-11, 23:18
Absolutely incredible. So much for their QC. IMHO, that company's quality has been slipping for years.
Interesting. I've got mine pulled out and I'm going to go measure the two holes. My 556 has a significant round count, but doesn't show any excessive wear. Do you think the hole might be eroded, or was it like this from the factory?
Also, if you get in touch with the guy who has extra's, let me know. Regardless of whether or not mine has problems, I like having spare parts around.
If the hole sizes are indeed 1.3mm and 1.6mm I having a hard time distinguishing them through measurement. The right hole looks smaller (i.e. incorrect), but I don't know if I can accurately perceive a 0.3mm difference. It is certainly not as obvious as in the pictures. I don't have a needle large enough to try the needle trick.
This Sig was made in 2006 if I remember correctly.
ETA: The piston assembly on Colorado Gun Sales website that includes the regulator is American made, not Swiss (you can tell by the piston). The Swiss assembly does not include the regulator.
Dirtyboy333
04-30-11, 01:38
If the hole sizes are indeed 1.3mm and 1.6mm I having a hard time distinguishing them through measurement. The right hole looks smaller (i.e. incorrect), but I don't know if I can accurately perceive a 0.3mm difference. It is certainly not as obvious as in the pictures. I don't have a needle large enough to try the needle trick.
This Sig was made in 2006 if I remember correctly.
ETA: The piston assembly on Colorado Gun Sales website that includes the regulator is American made, not Swiss (you can tell by the piston). The Swiss assembly does not include the regulator.
Oh ok, thanks.......Yeah i don't know where to get a swiss regulator but i don't even think i want one because the ports will be larger than what i already have.
Im supposed to email him tomorrow (Sat) morning and he is actually going to take the time and measure for the valve with the smallest GP and sell it to me (seems to be a very nice guy). I don't yet know the price or even have an idea of what their worth but being that their Sig USA regulators i don't plan on buying 1 unless its within $60-$70 and I feel thats even generous but i could be way off.
I'm VERY interested to know what size ports you have because my uncles is also an early 556 serial JS 006xxx and his has the .045" port that i want. I'm wondering if yours also has the smaller port compared to my newer 556 with a .052" port. Wonder if Sig USA enlarged them to correct some type of cycling issue?
An easier way to tell which port is smaller with the naked eye is to take the piston tube (?) out and look at the two gas ports thru the bottom of the piston tube. Its easier to tell bc of the area between the edge of the GP and where it meets the tube.
Mine do appear to be reversed, but the size difference is very small. I will be trying to dig out the calipers later today. Last night I could only find stuff measuring in fractions of an inch, and I could only tell that the ports are somewhere between 1/32" and 1/16". The measurements 1.3mm and 1.6mm fall in between those as well.
SO thankful I sold my 556 off and got what I had into it! :eek:
You're one of the lucky ones. A lot of people who bought when they first came out at around $1,600 are fuming...
You're one of the lucky ones. A lot of people who bought when they first came out at around $1,600 are fuming...
What pisses me off is the missed potential of the 551. I love the design of the weapon and feel with some minor improvements that it could be a serious competitor to guns like the SCAR. The 556 was a step backwards.
I paid 1400 for mine in early 07. Since then I've tinkered with it and changed out some parts, etc. It has been a good gun, not worth the cost, looking back, but it has provided me with enjoyment. All my other guns fill the "serious" role, so problems with my Sig don't bother me too much (and give me something to try and fix).
Just a thought, since they seem to be reversed, why not just run them in the reverse positions?
I am also wondering if this maybe accounts for some of the many failures encountered during serious training.
Just a thought, since they seem to be reversed, why not just run them in the reverse positions?
I am also wondering if this maybe accounts for some of the many failures encountered during serious training.
This is the most likely solution. What I want to know is if they are the right size either way.
Dirtyboy333
04-30-11, 20:03
Just a thought, since they seem to be reversed, why not just run them in the reverse positions?
I am also wondering if this maybe accounts for some of the many failures encountered during serious training.
Yeah thats definitely the best fix. But it's just another example of what Sig should have done right. Mine aren't reversed. I dont yet have any problems with my 556 but getting my P238 to run right is another story.
BTW: I slept in and didn't email the guy with the valves until now so ill probably get a reply by monday. sorry :lazy2:
It would be interesting to see what Sig customer service has to say about this.
I got the calipers out. The "small" port is ~1.6mm and the "large" hole is ~1.4mm. I am going to take it out tomorrow and shoot it to see if there is a difference I can feel (I've never changed the gas system).
If I notice a difference shooting tomorrow, I will contact Sig and see what they say. I hate dealing with Sig QC (I'd rather deal with HK; they treat me well), so if the ports are simply reversed I'm probably not going to bother with having it fixed. I'll just shoot the gun with the gas settings reversed.
I agree this could be a reason for premature part wear suffered by a lot of Sig 556 owners. I personally have yet to have an issue. It could also explain why this gun really chucks brass.
I'll keep everyone informed as I learn more.
Dirtyboy333
04-30-11, 22:48
I got the calipers out. The "small" port is ~1.6mm and the "large" hole is ~1.4mm. I am going to take it out tomorrow and shoot it to see if there is a difference I can feel (I've never changed the gas system).
If I notice a difference shooting tomorrow, I will contact Sig and see what they say. I hate dealing with Sig QC (I'd rather deal with HK; they treat me well), so if the ports are simply reversed I'm probably not going to bother with having it fixed. I'll just shoot the gun with the gas settings reversed.
I agree this could be a reason for premature part wear suffered by a lot of Sig 556 owners. I personally have yet to have an issue. It could also explain why this gun really chucks brass (though a strong ejector spring could also be the cause).
I'll keep everyone informed as I learn more.
So they reversed yours too. :no:
Like i said mine aren't reversed but theres not near as big as a difference between the two sizes. 1.32mm and 1.39mm
Reagans Rascals:
Yes the rifle fired fine with no malfunctions (I've shot several 556's, all with no malfunctions). Round count so far is only 247, all of which was Remington 55gr FMJ (L223R3) from WalMart. It is just a fun range toy, one more in the collection for friends, family and I to enjoy. I have tried to make it a 551 clone, as far as my wallet would allow. I believe the only US parts left in it are the barrel, upper receiver, and the semi-auto internals.
I would not use it (Or any other 556) for any defensive type roll. A true Swiss model yes, but even then I would choose a Colt (Or other reputable brand) M4 type weapon over it since I am so used to the ergonomics and handling of the AR series. Its just what I have been trained in, issued, and work with frequently.
Would I purchase it again? If the price was right, sure (And everyone's budget is different). But only as a toy- And only after a very careful inspection of the several problem areas that have plagued this US-made series. Just as we all should inspect any potential for-sale item. I've seen 6920's in GB auction photos that clearly had non-Colt uppers, no-name bolts or carriers... Know ahead of time what to look for, wear-and-tear areas to inspect, etc.
Rayd8 and KhanRad:
Yes I spoke to Sig Sauer and they are willing to take a look at it- Only after I give them my credit card number, ship the entire rifle to them, and pay full shipping. I offered to email photos of the valve, but the representative was not interested and outright refused to allow me to send just the gas valve.
A member of another forum contacted me on his own and offered to buy the valve, even after I disclosed the problem. I advised him to simply remember that with this particular valve, the rib should be straight up at 12 o'clock for the emergency setting and in position 2 for normal use (As SteyrAUG has suggested here).
I got the calipers out. The "small" port is ~1.6mm and the "large" hole is ~1.4mm.
Like i said mine aren't reversed but theres not near as big as a difference between the two sizes. 1.32mm and 1.39mm
That right there is simply amazing.
:blink:
I'm having visions of guys formerly employed by century arms with a coffee can full of various size drill bits on the assembly line.
Dirtyboy333
05-01-11, 02:47
That right there is simply amazing.
:blink:
I'm having visions of guys formerly employed by century arms with a coffee can full of various size drill bits on the assembly line.
:sarcastic: Yeah i know....They probably look just like I did about an hour ago with a Dewalt/Dremel and various bits from Midway that were worthless. lol
Although I did get nice setting(s) detents with a cobalt bit but theres no way im drilling the GP's. Ive tried alot of different bits and all have failed to cut or broke bc their so small.
Off to one of the thoasand or so machine shops in western PA. sucks :(
SIG 556, slumming man, slumming.
tomalibrando
05-01-11, 08:34
Is it possible the smaller hole is there when the weapon is fired with a supressor? Just trying to think outside the box a little. Generally, you choke off some gas when they are attached. On the other hand, if Sig said send the weapon back...maybe that wasn't the intent.
Yes I spoke to Sig Sauer and they are willing to take a look at it- Only after I give them my credit card number, ship the entire rifle to them, and pay full shipping. I offered to email photos of the valve, but the representative was not interested and outright refused to allow me to send just the gas valve.
This is why I won't bother sending it back to Sig. You would think at the very least that someone would be interested in the photos to possibly correct a potential long standing issue. But they aren't. If they were, they wouldn't have the problem to begin with.
My Sig has been refinished, had several parts replaced, etc. If I were to send it back, they'd just bitch that the warranty was void and ship it back to me, again, on my dollar.
DeusExMachina
05-01-11, 11:57
Sig 556...looks good but its just an expensive AK. :(
However, if they made a 5.45 version, I'd be all over it.
This is the most likely solution. What I want to know is if they are the right size either way.
Apparently, they can't even get their 7.62x39 version right.
Skintop911
05-01-11, 14:56
Photograph and mic the questionable components in detail.
Keep copies or logs of all communications with the factory.
Send it back to Sig and let or make them get it right. Accepting defective product tells the factory you don't care, and it's okay to produce them like that.
I noticed very little, if any operational difference between my two gas settings. I would lable the test inconclusive. I will be Emailing Sig later in the week, but do not expect to get anywhere.
My honest thought is neither setting is going to be as harsh as the "patrol" gas system anyway.
My brother and I checked his gas valve and the holes are the same, 1.15 mm
I noticed very little, if any operational difference between my two gas settings. I would lable the test inconclusive. I will be Emailing Sig later in the week, but do not expect to get anywhere.
My honest thought is neither setting is going to be as harsh as the "patrol" gas system anyway.
Dirtyboy333
05-03-11, 22:52
called sig yesterday and told them I had lost my valve at a class (lie) and they wouldn't send me one either. They wanted me to pay $55 to ship my gun back. I didn't do it
On some good news i finally figured out how to modify my valve and its very easy. Use an 11/64th HSS bit for the settings detents which will honestly make your setting lock up tighter than the factories. For the ports: buy HSS bits #56-60 and start with the smallest until you find what you like or google EDM services and a number of machine shops will EDM your GP's for you with +/- .002" tolerance.
Is it possible the smaller hole is there when the weapon is fired with a supressor? Just trying to think outside the box a little. Generally, you choke off some gas when they are attached. On the other hand, if Sig said send the weapon back...maybe that wasn't the intent.
This isn't the intent, but A friend of mine mentioned it when I brought up the point. It does make sense, but that is not the intent.
.
I got rid of my SIG over 1-1/2 years ago but it seems to stick in the back of my head that the way the two holes were ported was either one hole was used or both holes were used and not one or the other.
But I could be wrong ... I've slept since then??
But it's probably just me...
.
called sig yesterday and told them I had lost my valve at a class (lie) and they wouldn't send me one either. They wanted me to pay $55 to ship my gun back. I didn't do it
On some good news i finally figured out how to modify my valve and its very easy. Use an 11/64th HSS bit for the settings detents which will honestly make your setting lock up tighter than the factories. For the ports: buy HSS bits #56-60 and start with the smallest until you find what you like or google EDM services and a number of machine shops will EDM your GP's for you with +/- .002" tolerance.
Does having the holes in the top not mess up the gas system?
Dirtyboy333
05-03-11, 22:56
My brother and I checked his gas valve and the holes are the same, 1.15 mm
Thats the same size GP that my uncle has on his which i like. Newer 556's seem to coming with .052" like mine did but im modifying mine to 1.15mm (.045") shoots much nicer bc the action cycles slower.
.
I got rid of my SIG over 1-1/2 years ago but it seems to stick in the back of my head that the way the two holes were ported was either one hole was used or both holes were used and not one or the other.
But I could be wrong ... I've slept since then??
But it's probably just me...
.
Not quite right. Both holes are always used. One will be in "intake" and the other will be the "exhaust" the first post accurately explains the system.
I just pulled the gas valve out of my SIG556 classic and both holes are the same size. It was made in Feb of 2011.
Dirtyboy333
05-03-11, 23:06
Does having the holes in the top not mess up the gas system?
Im just waiting for the bit i need to get here to finish the job and i will let you know for sure BUT im already pretty confident that its makes no diff. bc ive talked to a few people who have done it and they said it works fine. Also, if you think about it the port that your using at the time is in line with the port in the bottom of the piston head so all the other ports are sealed off until you take the shot and the piston gets pushed back past the holes that aren't being used. By then the peak pressure has already done what it has to do. Go shoot your 556 and you will notice that the "out" port barely vents off any gas at all. The out port isn't activated until the piston head moves past it and it seems the pressures are very low by then. I know that after shooting 200 rounds through mine there was minimal carbon in and around the hole on the left side of the gas block where the out port is. If you wait 2 more days i will hopefully be able to tell you first hand what it does.
Dirtyboy333
05-03-11, 23:09
I just pulled the gas valve out of my SIG556 classic and both holes are the same size. It was made in Feb of 2011.
Thats just crazy. Mine was made in Sep. '09 and their barely different.
If you have the info on hand, do you mind telling what the diameter was? I'm trying to get a feel for when Sig started using the larger ports or if their just random sizes.:blink:
Im just waiting for the bit i need to get here to finish the job and i will let you know for sure BUT im already pretty confident that its makes no diff. bc ive talked to a few people who have done it and they said it works fine. Also, if you think about it the port that your using at the time is in line with the port in the bottom of the piston head so all the other ports are sealed off until you take the shot and the piston gets pushed back past the holes that aren't being used. By then the peak pressure has already done what it has to do. Go shoot your 556 and you will notice that the "out" port barely vents off any gas at all. The out port isn't activated until the piston head moves past it and it seems the pressures are very low by then. I know that after shooting 200 rounds through mine there was minimal carbon in and around the hole on the left side of the gas block where the out port is. If you wait 2 more days i will hopefully be able to tell you first hand what it does.
Yes, I'm interested in how this turns out. Good luck!
Dirtyboy333
05-03-11, 23:26
Thanks, i need some good luck....BTW: i just bought a brand new valve off that guy who said he has a bunch of 556 parts and he said that it "was measured at half a click under .05" which should put it right at .045"". He said he measured it with a reloading gauge and i really don't even know what that is.
I told him others were interested and he said that within a week or two he might place all his parts up for sale somewhere and he would let me know which i will in turn let you know. He only charged $50 plus $5 shipping. Dont worry, im still gonna drill the holes in mine and let you know how it works out.
Thats just crazy. Mine was made in Sep. '09 and their barely different.
If you have the info on hand, do you mind telling what the diameter was? I'm trying to get a feel for when Sig started using the larger ports or if their just random sizes.:blink:
I didn't measure them. I just looked at it and by the naked eye you can't tell a difference unlike a Swiss gun.
Dirtyboy333
05-04-11, 00:29
Ok, yeah if there diff you could tell with the naked eye. I can and mine are only like .003" different.
Here's the detents I drilled. The pic of the little dot is where I started the GP and then broke the bit. I have 6 HSS bits on their way from Midway ranging from .04" to .046".
http://i1230.photobucket.com/albums/ee498/Dirtyboy333/78cf2226.jpg
http://i1230.photobucket.com/albums/ee498/Dirtyboy333/b664eec0.jpg
http://i1230.photobucket.com/albums/ee498/Dirtyboy333/1590e1cc.jpg
http://i1230.photobucket.com/albums/ee498/Dirtyboy333/41dd0f2f.jpg
http://i1230.photobucket.com/albums/ee498/Dirtyboy333/962fa0f9.jpg
Looks good. Your friend's valves are around 1.25mm which is about right. I would like to get one if possible.
My brother and I checked his gas valve and the holes are the same, 1.15 mm
Unbelievable!
I just pulled the gas valve out of my SIG556 classic and both holes are the same size. It was made in Feb of 2011.
Ok, maybe I shouldn't be surprised at all.
I wonder how many unknowing customers are shooting their 556's in what they believe is the normal gas setting. Maybe this excess gas pressure is what was really causing all that bolt carrier peening discussed at another forum (That thread was around 26 pages), not just the little "shelf" inside the upper receiver that the carrier was impacting. I guess at least you two don't have to worry about that since your ports are the same size.
Dirtyboy333
05-04-11, 15:17
Thanks, the reason their much larger than the factory settings is bc the valve is so hard I had to place the bit with a firm rest on the flange. I couldn't just use the inside 1/3rd of the bit to shave a lil material out. It was way to hard. Like I said earlier it locks up very tight and has zero play when compared to the factory settings. Not that it matters bc the piston tube allows for a good bit of play.
Kisara, u have a good point. I know the carrier issue your talking about and even though the hump in the trunion shouldn't be there I'm sure it doesn't help to have your BCG cycling too fast. I bet there's alot of people who don't realize the're running their 556 on the "emergency setting".
Dirtyboy333
05-17-11, 00:57
Yes, I'm interested in how this turns out. Good luck!
Everything worked out greatly on that project......It was well worth it!!!
If you want details, just lemme know
Littlelebowski
05-17-11, 06:19
This is hilarious. Where's S1?
variablebinary
05-19-11, 19:31
This is hilarious. Where's S1?
Who needs a gun built to high standards when it "just runs"?
Maybe the out of spec parts are really a feature?
eternal24k
06-22-11, 16:10
anybody know where to buy the Swiss valve?
"Sig: To hell and back" . . . because that's where you'll want to tell them to go.
My old roommate had a mid '90's P229. I hope he kept it. Got to have some reminder of when Sig made good stuff.
eternal24k
06-22-11, 18:16
"Sig: To hell and back" . . . because that's where you'll want to tell them to go.
My old roommate had a mid '90's P229. I hope he kept it. Got to have some reminder of when Sig made good stuff.
they ditched (or maybe Sig, Germany forced them lol) the Hell and Back slogan and now have "When it Counts", maybe they were referring to their warranty.
Dirtyboy333
06-22-11, 18:33
anybody know where to buy the Swiss valve?
I could direct you to a guy (who u probably already know) who said he has a pile of valves but I don't think he knows which ones are Swiss or US.
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