SIG SG 55X and 556: Technical Data & Test Doc., Armorers Manual and More

[Janq]

Preface:

This year I've had now three conversations/debate discussions as related to the design intent and testing measure of the Swiss Arms/Sig Sauer 55X series carbine and rifle as related to the latest variant of the line, the US market variant '556'.

Below are documents that should assuage anyone's thoughts, ideas, or doubts that the 55X series is not only as reliable as the US base Stoner designed M16/M4 (5.56) and AR-15 (.223) but is in fact far more durable and reliable as related to functional design, action, and assembly as components and firing assemblies.

Note that the US market variant '556' is _functionally_ exact same as the Swiss Arms/Sig Sauer 551-SP 'Sporterized' international market variant which is semi-automatic only rather than being select fire. The 'SP' model was developed for sale amongst the Canadian civilian market. Otherwise the 55X series up to the 556 has been an NFA Class III type firearm with select fire type fully automatic firing capable action as for application by military and law enforcement exclusively.
Outside of Canada prior, and now the US, it generally has not been available for sale to civilian markets. Unlike that of the AR-15 in specific. This is one of many reasons why the aftermarket for the 55X series is not as mature even as the firearm series has been around since 1980. Further the Clinton Administration passed bans against import of foreign military-style weapons without regard to their action type[/u] either as complete assembled rifles and as parts which prevented the 551-SP in specific from being imported. That ban continues to current.

That is why Sig Sauer, formerly Sig Arms of North America, developed the 556 variant. The lower/receiver is US made and the barrels are Swiss blanks unfinished that are mated to the upper as in finished condition here in the US in NH. In doing these two steps the rifle then becomes serialized in America, rather than Switzerland, and thus meets and beats the Federal law requirements becoming an 'American made' and NFA compliant as semi-automatic only carbine/rifle, as opposed to 'assault weapon'.
Somewhat complicated but not really if you understand current firearm laws and regulations. It is what it is and with the US military up to re-compete toward a new base carbine and rifle system in to the current and near future this was the no-brainer time for Swiss Arms/Sig Sauer to make this step. We civilian customers have benefit only now due to that timing as the opportunity was non-existant in years and decades prior.

Many people are completely unfamiliar with the 55X series as outside of Canada it has largely been an unknown commodity amongst North America through out it's _thirty year_ history as a largely non-commercial military arm.
By that unfamiliarity in addition to it's being a more than natural competitor to the dyed in the wool amongst Americans M16/M4/AR-15 rifle/carbine system some folks have blown off the 556 in specific as being 'garbage' or for lack of understanding how the system functions and the basically minor differences between it and the rest of the 55X series.

The most notable _functional_ difference between the 556 and the rest of the 55X series is in it's magazine well, the magazine it uses, and the magazine release.
The 556 is designed to accept and support STANAG type M16/AR15 magazines. If the magazine will run in your AR then it will run in the 556. Period. And as based on the 55X series' internal design which is much less complicated then that of the Stoner design those same mags will very likely run _better_ and more reliably in the 556, as well magazines you have lying around that do not run reliably in your AR will likely run fine with no problems in the 556 (!). Why this is will become quite obvious upon review of the Armorers Manual provided below which details the firearms action and/or direct inspection of a 556 variant.

The items below should help most anyone much better understand what the Swiss Arms/Sig Sauer 55X series is and in specific what the NA market Sig Sauer 556 has to offer, which is now available in multiple carbine variants as well as a factory short-barreled rifle (SBR) to compete against the Colt M4 as well in stockless pistol format and with a 24" long barrel rifle called the 'DMR' (Designated Marksman Rifle) that has been in development also for the NA market as based on a prior 55X variant called the '550 Sniper'.

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SIG Assault Rifles - SG 550 / 551
Technical Data and Test Documentation



IMPORTANT NOTE


Both weapon models. the SIG assault rifle SG 550 and the short-version SG 551, have been submited to the full range of endurance tests, verification tests and quality inspections described in this:

Technical Data and Test Document

SG 550 & SG 551


Contents


I. Endurance Trials

- Purpose
- Procedure


1. Barrel life expectancy: Test procedure

1.1. Firing sequence

1.2. Inspection and measurement

2. Weapon service life (guarantees)

2.1. Service life of individual components

2.2. Extended service life / Functional safety

II. Verification Tests

1. Rain trials

- Purpose
- Procedure
- Conditions
- Verification of accuracy
- Results


2. Sand and dust trials

- Purpose
- Preparation

2.1. Stationary sand and dust trials

- Procedure
- Results


2.2. Dynamic sand and dust trials

- Purpose
- Preparation
- Procedure
- Evaluation
- Results

2.3. Sand drag trials

- Purpose
- Preparation
- Procedure
- Results

2.4. Mud trials

- Purpose
- Preparation
- Firing
- Conditions
- Procedure
- Results


2.5. Testing under extreme temperature conditions

2.5.1. High temperature testing

- Purpose
- Procedure

2.5.2. Low temperature testing

- Purpose
- Procedure
- Results



2.5.3. Icing up tests

- Purpose
- Procedure, test no. 1
- Procedure, test no. 2
- Results



2.5.4. Cold tests, Jungfrau Joch

2.6. Functional reliability of unlubricated weapons

- Purpose
- Procedure
- Measurement of cyclic rate
- Results


2.7. Plastic magazines: Drop tests

- Purpose
- Procedure
- Requirements


III. Quality Inspections / Acceptance Criteria


1. Quality Assurance

1.1. Quality assurance programme

- Execution, surface and heat treatment
- Springs
- Barrels
- Functions testing
- Dimensional testing
- Overpressure proof firing
- Zeroing the weapons

1.2. Accuracy trials with various makes of ammunition


IV. Interchangeability of components and sub-assemblies

The full document including results can be read at; SIG 550 / 551 Technical Data and Test Documentation


~~~

SIG 550 and 551 Armourers Instructions
http://www.biggerhammer.net/sigamt/5...ers_manual.pdf

Note: I d/l this for archival purposes _and_ printed off a hard copy to file.
Do not print this unless you do not mind buring through a lot of paper. As well know to _remember_ to select reverse printing amongst your defaults (!). I learned this the hard way.

Swiss Army SW90 (550/551) Maintenance Manual
http://www.nvbmb.nl/downloads/65-364-d.pdf
Note: If you do not read Swiss, do not bother to click. I provided this more for archival purposes than anything.

Sig 556 'SWAT' model (full rail front end) Field Strip
YouTube - Sig 556 Swat Field Strip

~~~

Images of Swiss _citizens_ carrying government military issue SG550 (rifle) openly as they go about their regular civilian area day, which is normal in Switzerland as per their laws and social views as related to arms, security, and 'home land defense' in general.
Very much different than America, American view toward arms at large, and our own laws & government.





Credits: Tim Orrock - Swiss Stuff pictures by Tim_Orrock - Photobucket

Additional reading regarding Swiss firearm laws:
* http://www.guncite.com/swissgun.html
* Gun politics in Switzerland - Wikipedia, the free encyclopedia
* BBC News | EUROPE | Switzerland and the gun
* http://www.republicofalberta.com/Swiss.htm
* Guns, Crime, and the Swiss - by Stephen P. Halbrook
* US vs. Switzerland Gun Laws
* Gun Control: Myths and Realities | David Lampo | Cato Institute: Daily Commentary

~~~

Additional reading:
Series 55X including; 550, 551, 552, and 553
* SIG SG 550 - Wikipedia, the free encyclopedia
* The STG.90 Page
* http://www.sigsauer.com/upFiles/CmsC...SG550551OM.pdf
* Modern Firearms - SIG SG-550 SG-551 SG-552 Stgw.90 Assault Rifles
* SIG SG 550/551 (Stgw 90)
* SIG SG550, SG551 (Stgw 90) and SG552 Commando 5.56 mm assault rifles (Switzerland) - Jane's Infantry Weapons
* The SIG 550 a New Assault Rifle for the Swiss Army
* SIG SG-550-1 Sniper Rifle
* Disassembly Of A Swiss Army Stgw90 Aka SIG 550 Assault Rifle - Video
* YouTube - 300meter sniper by swiss (Chinese) recruit

Series 556 including; Classic, SWAT, Classic SWAT, SCM (restricted/AWB states model), ER, and Pistol
* Products & Services
* Products & Services
* Modern Firearms - civilan guns for self-defense, training and hunting - SIG 556
* GUNS Magazine May 2008 Feature
* SIG's 556 SWAT
* SIG 556 SWAT Gas-Piston-Driven Tactical Rifle/Carbine/Subcarbine
* Tactical-Life.com Sig Sauer SIG 556 5.56mm
* Sig 556 SWAT Review – Bill from Niles Michigan
* SIG 556 :: Index
* YouTube - sig 556 ('Michael Bane Review')
* YouTube - SIG 556 Gas System ('SIG 556 Gas System')
* YouTube - SIG 556 & AK47 Cousins ('SIG 556 & AK47 Internals Comparison')

- Janq

"The Swiss are well armed and enjoy great freedom." - Machiavelli, 1532

[DefensiveCarry.com]

[BAC]

And with all this we still notice: A) a lack of operational history, and B) the reaction in general to the 556 can be best described as 'tepid'. Americans wanted a US-made 550/551 that took AR magazines, and the US side of Sig could not deliver a product that impressed US consumers. Even die-hard Sig fans have noticed that quality of the 556 is not on the same level as the Swiss made 55X series and Sig pistols. Add to this the Chinese copies of American-made dot sights and you've got yourself a ball game.

Just a disclaimer: I'm not stating that the 556 is a crappy rifle. It feels crappy with the cheap furniture, true, but it might well be a viable rifle. It has not, however, convinced many people that it offers distinct advantages over the AR platform given its overall execution and price point, and did not meet market expectation for what Sig fans wanted in a Sig-made rifle.


-B

[Janq]

BAC,

The 55X series has 30 yrs. of operational history...OUS.

Toward 'B' it is a 551...that supports AR magazines.

US Sig 556 Classic

Source - http://www.sigsauer.com/Products/Sho...&productid=114

Effectively in aesthetic and completely same in function a '551', that supports AR/STANAG magazines.
The 556 though does so with a stouter yet lighter forged and milled lower than the OUS 55X series stamped and folded sheet metal.

OUS Sig 551-1P

Source - http://www.remtek.com/arms/sig/551/551p.htm

Which singularly by aesthetics American video gamer and Airsoft type buyers amongst others were hoping to get as a 'real thing' just like in games match to their toys. The vast majority of complaints from it's first debut at SHOT '06 to current has been as related to aesthetics of the lower and not having originally shipped with the same type SAN stock. Which is now available.
Oh and the Safe and Fire markings are not painted red and white like on the Swiss guns, which folk are doing themself at home with a horsehair brush and a model paint from Testors. Really stuff that is not a big deal or even an item to comment toward on the whole.

As to distinct advantages over the AR I guess you did not actually click and read the above link toward the 'Technical Data and Test Documentation'.
The folks who are crying about the giveaway dot sight as on the SCM are lame. It's a $49 item. And it's not like serious folk don't already have an EOTech or ACOG sitting around. And if it did for some odd reason come OEM with an EOTech then the price would be higher and folks would be crying about that and how they already have one so why should they be forced to add another. Those arguments are weak.
And as to overall price that too is weak considering folk are paying same and _more_ for ARs as 'upgraded' to have piston top ends and increased durability via Noveske and many others. Who cost more (!).

Now if you had mentioned something serious like ehh but it weighs a pound more than an AR then I'd be yeah you got something there. It is heavy as compared to an AR. And it would be far heavier if the lower had been the same as the stamped, folded, and welded steel of the 551.
But then it's not like folks aren't kitting out their ARs with all manner of rarely if ever really used rails and what not bits that are not themself weightless. Civilian world never mind military.

As to the furniture that too is a weak complaint as the whole of the 55X series includes polymer furniture exact same as the 556 albeit without pic mounting rails which of course folk would have complained about if the 556 had shipped as such. Today though for those who do not like what ever furniture came with their particular model 556 they can very easily swap it out for any other of their choice including the OEM full rail front if they deem as much to be necessary.

Bottom Line:
Pull the trigger and as long as it's got a mag loaded with live ammo the 556 very likely will go bang every time. And do so reliably with accuracy. Personal view toward non-functional aesthetics and furniture preference aside.

- Janq

[bonehead]

Great post Janq. Will take me a while to visit all the links:)
My biggest 'complaint' with my SWAT are 1) the ridiculous tolerances between the metal interfaces. The SWAT rails are IMPOSSIBLE to remove on my rifle. Took me a good 3 hours, a punch, and a big ol' hammer to knock them free of one another.
2) the weight. I have no extra tacticool accessories mounted....yet (ACOG incoming), but this thing is quite heavy. Perhaps one of the reasons aside from the gas piston mechanism that it's SOOO very soft in the recoil department.

[Janq]

Agreed...The SWAT variant is heavy.
Frankly I see no need for all that metal on any carbine including ARs, and all it does is chaffe your hands requiring gloves and/or rail pads. But hey it 'looks' cool. :|

I have the SCM model with the non-Classic original furniture that includes three small pic rails. For me that's perfect. Two rails for a light or what ever and a third underrail for a bipod if desired.

For my own purposes I use the receiver rail to mount an EOTech 511 I had laying around as positioned forward in a 'scout' style and I'm pretty much good to go.

- Janq

[BAC]

BAC,

The 55X series has 30 yrs. of operational history...OUS.

30 years of relative peace is not a good measure on the effects of true war-time use on a rifle, which is precisely my point. The lower being more stout is a wash, since the upper is folded sheet metal and is more important to the functionality of the weapon.

Anyway, you seem to have missed the main crux of my argument: Sig as a company did not satisfy their intended customers with their rifle. The customers expected a 55X that takes AR mags. The customers got a rifle based off the 55X series with no irons (until newer models), a POS red dot on some, non-original (crappy) furniture, a sheet metal upper with a screwed on rail (that too often is canted, sometimes moderately and sometimes severely), and the wrong stock. Add to this some very non-Sig-like quality control issues and you have a group of bonehead mistakes that never should have happened, but did. Poor execution. Sig even knows this, which is why the had to go back and release the 556 Classic.

Let me repeat another caveat you might have missed: "It has not, however, convinced many people that it offers distinct advantages over the AR platform given its overall execution and price point, and did not meet market expectation for what Sig fans wanted in a Sig-made rifle." None of that was unclear, and none of that could have been read as a personal criticism against the platform. Whatever technical merits the rifle has, it did not in its initial release impress anyone. Bad first impressions are kind of a big deal. Hardly a weak argument when you're going to put the fine name of Sig behind a firearm to sell it.

The overall service life of the 55X rifles is about the same as a rack grade M4 Carbine, and I'm willing to bet that given the QC issues Sig's had with the 556 its service life won't match the Swiss rifle it's based off of. "Greater" reliability has not been demonstrated, and Michael Pannone has shown how to keep a rack grade M4 running for 15k rounds over 31 weeks with no malfunctions resulting from the weapon (9 malfunctions overall related to bad ammo/mags) and he went about as long as the linked test described between cleanings. Accuracy, while good, is no more impressive than a rack grade AR.

I remain unimpressed. The market apparently agrees.


-B

[bonehead]

Agreed...The SWAT variant is heavy.
Frankly I see no need for all that metal on any carbine including ARs, and all it does is chaffe your hands requiring gloves and/or rail pads. But hey it 'looks' cool. :|

I have the SCM model with the non-Classic original furniture that includes three small pic rails. For me that's perfect. Two rails for a light or what ever and a third underrail for a bipod if desired.

For my own purposes I use the receiver rail to mount an EOTech 511 I had laying around as positioned forward in a 'scout' style and I'm pretty much good to go.

- Janq

Hey, the SWAT is more than just 'tacticool'. I'm very happy with the quad pic rails. Will mount the ACOG on top (debating on a Larue mount), looking for a good rail mounted sling attachment (not sure which, HK-style perhaps) which I can place on the left or right rail. The forward griplight attaches to the bottom rail. It's great....if you like shooting with a VFG. I promptly took mine off and it's sitting in the safe. Undecided on a bipod. Harris or if I decide to go back to a VFG, one of the integrated deals (T-pod or similar).

No chafing issues; I attached the rubber rail grips that came with the rifle.

Now, if I could only find a 'reasonably' priced Magpul UBR......

[Janq]

I know I was just ribbing ya. :p

- Janq

[Janq]

BAC,

The market has had access to the weapon only just under 18 months. It's a bit early to be making any calls to that end as based on that reflection alone.
Especially considering that in the US the AR didn't become a notable seller either for a decade. I'd caught your caveat and addressed it prior without specific comment to the market for the reason that again it's only been available to US buyers some 18 months. And many of them don't understand the system nevermind are entrenched and even highly invested in the AR system.
I don't think anyone nor Sig would have seriously expected some huge wave of AR buyers to drop into a completely different weapon system, even as it does support AR magazines. In fact Sig production was set low and they have been caught flat footed by orders having to increase production to meet demand. These things aren't exactly sitting on shelves dusty and rusting. They just aren't as big in demand as the AR which is not to be expected.

As to irons it does come with irons. Just not the kind like on an AR.
A standard front either foldable on some models and fixed on others. While _all_ came with rear sight that is built into the guns top rail and folds flat into a flush milled out and out of the way shelf for use during emergencies. It is adjustable for elevation while the front sight is adjustable for windage. It works. Just not like on an AR.
As to the 556 Classic the only thing different about it from the first model is that the front end furniture is smooth per customer requests and again the stock is like the SAN version which again folks wanted, largely for reason of aesthetics. The rest of the gun is completely the same .That does not make it crap (?).
As to the upper being stamped, folded, and welded steel it's strong...very strong. The lower was not built that way because for design purpose to best support the STANAG mag it made the most sense to go that route being the mag is completely different than the 55X proprietary magazine.
As to quality control that issue was long ago resolve specific to the fist few hundred off the line that had different tint but not color upper and lower finish and even fewer had receiver rails that were not true resulting in some tight fits of accessories to the rail at the forward end. Revised in production and recognized in the first few months. A long ago gone problem resolved. Not that either was an issue that affected functionality. There has been no other QC issues to speak of that I'm aware of.

I hope I addressed all of your multiple points and didn't inadvertently drop one.
The AR required nearly 40 yrs. and multiple production and design revisions to get to where it is now as among the market. Under military testing less harsh than that of the above citation the M4 in specific came in last amongst it's contenders and at that experienced a total amount of failures equal to greater than the total amount of failures from it's three other competitors (!).
Mike Pannone has shown how to keep one running for endurance, BUT what is involved to do so is not an off the rack weapon system either and he did involve maintenance in changing of the gas rings mid way through and his suggested tech requirements to allow such include by his own words; "Overhaul the gun every 5,000 rounds...Use the existing and proven BHI Enhanced M4 SOPMOD Bolt Upgrade Kit (extractor/spring and Crane O-ring, extractor pin, gas rings)".

The 55X series has no such issues nor armor level maintenance requirements or operational caveats, at such low round count figures. And unlike a Noveseke VTAC as he used, which again is not an off the rack weapon but is in fact a highly customized and optimized refined AR syetm, it does cost considerably _less_ at straight retail than that of $1975.35...if you can get hands on one as the Noveske website for the VTAC he used currently states;

WE ARE NOT ACCEPTING RIFLE ORDERS AT THIS TIME.
Rifles will be available when they are in stock and ready to ship.

Source - VTAC Rifles - Noveske Rifleworks, LLC. Precision Battle Weapons - NoveskeRifleworks.com

Post Obama gun rush prices on the 556 have been dropping to below MSRP rates (many folks had been paying MSRP+) in kind with other weapons of all sort. No such case though with Noveske in specific.

Anyway you don't like the 556 that much is clear. There is nothing wrong or unlawful with that. Yet. ;)
I don't work for Sig and don't get a dime if you or anyone buys a Sig anything. I'd posted this thread as informational to counter much in the way of incorrect and misunderstood supposition that is out there. Much of which includes what the weapon system is and is not and does or does not do, and how it is not a 55X series carbine when in fact it pretty much all is a 551-SP with exception of the US market specific lower so as to largely beat the Clinton ban law _AND_ to support STANAG/AR mags which in this market was simply a necessity.

- Janq

[bonehead]

Finally slapped on my last accessory for this one.
She's 'ready':)

[j3313]

I a Sig 556 swat classic and fired over 500 rds with no problems and one cleaning. It has a smooth trigger, much better than my bush or colt. the only minor complaint I have is the front end is heavy. I also mounted an eotech 512 with a 3x magnifier which produces excellent performance at 100yds. j3313, sneaky pete