Sig 556R 1,260rd ‘Stress’ Test

Up until a few days ago I had never really had an interest in SIG rifles; I had no need for another .223 rifle. And then I saw this one. The shop that I work with(They do title I guns, I do Title II and gunsmithing) received a shipment of the new Sig556R. I love the 7.62x39 round, it’s cost and ballistics are great. But I’ve never been a guy that was a diehard AK lover. I'd contemplated for about a minute an AR upper in 7.62x39 but scratched it. Finally it seems Sig has released the gun that I wanted, well designed, fires 7.62x39 and does not take a proprietary magazine.
However, I knew that would not be happy with the gun unless I knew it would run, so a quick discussion with a friend and we came up with a ‘Stress test for the gun. In the morning we would fire an entire case of ammo through the gun, in a short period, and try to see what would break.
The Gun:


I got the gun last night, I checked the box (28 Feb manufacturing date) and looked the rifle over. I made sure to not clean it or lube the gun; I left it coated with the factory assembly lube. My desire was to stress the gun, and this way I would not be doing anything to it beyond what the factory did.

The ammo
I had several cases of Yugoslavian Surplus Ammo on hand and it made the most logical choice. It was brass cased, M67 bullet and known to be a good shooting load. And it came in a convenient case of 1,260 rounds. And once you open a case you are not allowed to stop

The Test
Early this morning we loaded up, drove to our favorite secluded desert shooting spot(which already was half full) and set up camp, we had brought a few other guns to keep us from getting bored but it was time to test the Sig 556R. There where 4 main shooters, Myself, AZS member AZDevil, and two others who shall be nameless



We ran through both steel and the included polymer magazine. We slow fired the gun, rapid fired it and even had one guy who was a master at getting it to Bumpfire(A good way to burn through ammo!) We experienced exactly two malfunctions:



A failure to eject during regular fire, this occurred after about 900rounds; and another, a failure to feed during a bumpfire session. Both malfunctions were easily fixed with known remedial action drills.



Once done shooting it was time to head back to the shop and check out how the gun handled 1260rds in a little under 3 and a half hours of shooting.
All 4 shooters had a good feeling on the gun when we finished, the biggest complaint was the heat produced by the gun, with no heat shield and a thin hand guard, heat buildup was much worse than with an AR15 or AK47

The Results:
I’ll start with the issues I saw as soon as we started tearing down the gun, the lower is Aluminum and does not handle the steel magaziness well, there was a noticeable amount of wear on the Magazine Shelf area.



A solution to the issue would be a steel insert for the entire shelf area, not just the top of it.
The other major issue pointed out by AZDevil was the fact that the majority of the screws used on the gun were loose now. No locktite had been applied at the factory. A quick session of locktite application and this issue was fixed. However I did end up losing the rear sling swivel due to this.



Other then these two issues the gun was in good condition, if dirty and very dry. We estimated that somewhere around the 3-400 round mark that the factory lube was used up, the gun required a good swipe of the charging handle or it would not charge the gun on mag changes.
All told I am very impressed with the gun, we did not bench the gun (that is the next test) but all parties commented that the gun was quite accurate. It was also extremely reliable. I purposely had us beat the gun up but it kept running no matter what we threw at it. The next major test is to see if it truly is more accurate then other 7.62x39 weapons.




















 

Great write up.  I had the same kind of malfunction where the spent case got caught by the returning charging handle with mine when I ran it through a carbine class.  Going to use only poly mags in it to avoid wear on that aluminum mag shelf too.

Son of a b!tch. I thought I was done buying for this year. I built a x39 AR upper already because I wanted something in x39 more accurate than an AK. If some successful suppressed 556R reviews start popping up I may ditch the AR and get the 556R to compliment my 556 and 522.

Thanks for the write up.

ETA: How are you going to clean it? I was planning on dunking my AR in a tub of hot water and follow with boiling water like my Mosin minus the stock.

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mine had the same failure to eject problem once too. on mine it actually pushed the plastic cover off the charging handle.

Could the plastic piece be removed and would that remedy this issue?

Already done cleaning. I used ALOT of foaming bore cleaner, it's high in ammonia and being a foam kinda sits and works for you, I detail stripped the gun, and just soaked everything while I did work for customers and then cleaned away. Really for the number of rounds that went through the gun it cleaned up fairly easy. The worse part was the gas system, the plug and tube had become bonded with carbon and needed a bit of persuasion to come apart.

I am wondering if a after market handle with a profile that dips down would fix it? The failure was not a big deal to me, a quick swipe of the charging handle cleared it and the gun was running again.

It may well, I'll mess with it tomorrow., I noticed that the mouth of the case put a divot in the plastic portion of the handle

the plastic piece can be removed but i dont think it would stop it or that i would call it an "issue".



it has happened once in 600ish rnds in mine and only once in 1260rnds in the OPs.

It really seemed to be ammo related to me, We'll see how it runs from the bench with US ammo next; and then to feed it a miss mass of steel cased crap

thanks for the great write up, good to see someone putting it to the test.  Nice work !

so far every round through mine has been golden tiger FMJ. i still have a few light primer strikes with this ammo. it always goes off the next time through the gun. the second time i brought it to the range i grabbed some fiocchi brass cased boxer primed ammo to try but im a fucking idoit and grabbed the boxes full of spent casings i plan to reload for my x39 bolt gun instead of the boxes with actual ammo in them.



i picked up a new pistol yesterday, a RIA 1911 in 9mm i still havnt shot. some things came up and i couldnt make it to the range this weekend, and next weekend ill be on call for work, so now i got a 556R with new iron sights that i cant sight in and a new pistol i cant shoot for 2 weeks. sucks to be me.



ill make sure to go to the range by myself next time so i can spend time taking pictures and doing accuracy tests. hard to do when you're teaching 2 new shooters.



also havnt cleaned mine yet. i usually clean my rifles once a year, if im in the mood. just keep adding CLP and they are good



edit: oh yea someone warned me about the loose screws on mine so i had alraedy locktighted the rail screws before the first range trip. after the second range trip i decided to look at mounting a sling and noticed the rear sling mount can be flipped around, and mine was loose as hell. i almost lost it like you did. i flipped it around (me being left handed) and locktighted it in there.

Not really worried about losing the sling mount, it was popping me and my friend in the nose; so it was going to come off anyways.

Glad to hear you've had good luck with the Russian ammo in it, I've got a decent amount of Yugo ammo but want to try out the other stuff for just in case.

Tim,

Awesome review!  I am hoping they come out with a Patrol version of the rifle eventually- SBR the Patrol and it would be a 21st century Krink!

As to the mag shelf wear, you might want to contact SIG about that- if you got that much wear on only 1200 rounds, I don't think the receivers are going to hold up very well long term and they may want to look at a  steel insert at that location.  Other than that one issue, it looks like a pretty nice package overall.

I am assuming the gun does not have a bolt catch?

[ETA]  I see in another thread it actually appears to have the bolt catch lever- does it just work manually since AK mags can't actuate it?

I wonder if a AR mag adapter would fit properly and you could run 7.62x39 AR mags (more out of curiosity than anything)

We were doing some rough mag changes, using the ak method of pushing the old mag out with the new one. Right now I am going to run poly mags until I figure out another solution

As for the bolt catch, the mag does not activate it, but something may be made to work.

How about the stock?  Is it the same one they put on the 556 or did they beef it up for the larger round?

I haven't handled the regular 556, from the looks of things it is the same. Seems to have held up fine.

Thanks Tim for the great review and looking forward to your bench report!

I am seriously considering this rifle, but concerned about the mag shelf & money already invested in metal mags.  Is there a successful drum mag tested yet?

Obviously I'm new here and again thanks for all the participants feedback.

MC

Honestly the more I think on it, this must be why SIG shipped the gun with the Polymer magazine; how could they not know that a steel mag would tear up an aluminum shelf.
It's not a deal breaker for me as I have AKs that I can use the steel mags with and I know in a pinch I could use steel mags for the SIG 556.

I am considering having the area milled out and a new one piece steel insert made.

Youre left with a limited selection of mags if you cant use steel.  The bulgarian circle 10's have steel, and so do the US palm mags (stainless steel).  not sure about the tapcos, but if thats the only thing you can use I think I'll pass.  I believe this is a serious issue that needs to addressed, I for one was interested in one but not anymore.

Nice review. I was wondering how the mag interface worked. If you take it easy the aluminum should hold up ok I think. Not a fan of the bolt on parts Sig has used though. The PTR-32 I have is all steel of course with nicely welded in mag adapters. That said it remains to be seen if it can be made to reliably run with a variety of mags. Looks like the Sig is GTG in this regard. Think I'd have to get a patrol version if offered. Its a maybe on the standard otherwise.

Thank you very much for the excellent report.  I doubt any of the gun magazines would have mentioned the aluminum lower receiver wear where the magazine fits.  I am looking forward to your range report in regards to accuracy when you get the chance.  If it shoots decently, and I am sure it will, then I will have to get one of these if Sig addresses the magazine well wear issue in an updated version.  Again, thanks again for posting a very thorough review.

If the stars align I will be shooting tomorrow morning at the local range. Will only have a couple hours though.

Made it out to Rio Salado Sportsman Club this morning. I shoot 100rds through the gun this morning, no problems of course. I will also state that I am by no means a good shooter from the bench, a friend who is a great bench shooter was going to show up but he canceled at the last minute. I blame myself for some vertical stringing you'll see later.


Here is the setup for this portion of the review
Sig556R, Trijicon TA31 ECOS 4x


Gun Zero'd at 25m with minimal rounds (~8)
Moved out to 100yards


First String, 7 rds of Yugo Surplus M67 ball

Mean was 1.7inches
Max was 2.5inches

Second String, Winchester 'Whitebox' 123gr FMJ, 10rounds

Mean was 1.7 inches
Max Horizontal was 1.2 inches
Max Vertical was 3.2 Inches

Third String, 30rd of Yugo M67 fired rapid

Mean was 3.1inches
max was 5.8 inches

Fourth String was 10rounds of Winchester fired Rapid with the gun hot

Mean was 2.7 inches
Max was 4.8inches

Rest of the Ammo was fired at the 300yard Steel, which was very easy to make ring.

I was very happy with the gun, a bit unhappy with myself.
I am going to try and pick up some of the new Hornady VMAX ammo and see how it runs

Well done folks.

Got 2 boxes of the Hornady SSTs, trying to find the tine to go shoot them

There have been issues reported with Wolf so...
I ordered a box of every type of 7.62x39 JG sales had in stock(They were out of wolf but I have that) Hopefully I can run a test this week.
I'll try to get video.
Also will try and find the time to test out the Hornady SSTs

Did some measuring this morning.

Sig556R Firing Pin Protrusion; .065
AK Firing Pin Protrusion; .08

Got out to the range to shoot some Hornady SST, very nice, grouped right around 1 inch

My ammo from JG showed up after I left the range so the wolf remains to be tested. The Hornady loading are steel cased so it isn't the steel that is the issue.

AIM has these  for sales but I've seen both good and bad  reviews. So I was hesitant. I have  to say this may change my mind.

and here i came to read about gripes complaints and faults to sway my opinion against getting one.......damn looks like I'll have to pony up for one.

Steel Case Ammo report;
I fired 20rd of each of the following boxes of Ammo. I also fired a few mags of Yugo with no issues.
Brown Bear SP No Issues    
Brown Bear HP No Issues
Brown Bear FMJ No Issues
Golden Bear FMJ 2 FTE(Fail To Eject)
Golden Bear HP 1 FTE
Seller & Belliot FMJ No Issues
Silver Bear FMJ No Issues
Silver Bear HP No Issues
Silver Bear SP 4 FTE
Tula 122 FMJ 2 FTI(Fail to Ignite) All rounds fired on second strike, all that failed first strike had very deep set primers
Tula 124 FMJ 3 FTI, All rounds fired on second strike, all that failed first strike had very deep set primers  
Tula 124 SP No Issues (Lucky I guess)
UCW 122 FMJ No Issues
Wolf SP No Issues
Wolf FMJ (Black Box) 2 FTI All rounds fired on second strike, all that failed first strike had very deep set primers
Wolf FMJ (Camo Box) 3 FTI All rounds fired on second strike, all that failed first strike had very deep set primers
Golden Tiger 2 FTI (I saved one, the other fired on second strike


Typical Fail to Eject

Thanks for the testing Tim, it's unfortunate that you had so many FTI and FTE's.  It would seem that as long as the Yugo surplus holds out you'll have no issues with the rifle.  Unfortunately, it doesn't seem like the rifle is 100% with various flavors of affordable Russian ammo.

I luckily have stockpiles of the Yugo.

I am going to re order the ammo that FTE'd and try it on the open gas setting.
Contemplating how to fix the light strike issue. I may do some mods to the firing pin.

I am not giving up on the gun, it shoot MOA with the Hornady SSTs.

I may call and bend the ear of my Sig rep on this

That is the best option. Sig needs to be working double time to get a longer firing pin made for these.

I would be interested in hearing what your Sig rep has to say about the issues.  



 

Were all the failures with Tapco mags?

 

I used Tapco's exclusively that day. I check the mags by running a full 30rds of Yugo through them when I bought them. When I get a chance to test the gun again I will run the second gas setting and use steel mags if people want

Talked to our Sig rep today he was very receptive; took notes(!) And promised to pass info up higher.

another 400rds with no issues today, half of them through the suppressor (yugo and UCW ammo)

Thanks for all the info!

I was leaning hard toward the PTR32, but at the same price and with nearly 30% weight savings.... Sig might be the way to go.

Now I have to try and decide if I want to wait to see if a Patrol model comes out (easier to SBR, as the only mod will be the barrel, nothing on the gas system).

I don't know which one to buy, the PTR or the Sig, can anyone tell me how accurate the Sig rilfe is out to 200yrd?

Kinda how I feel.

So How long should I wait to get one of these,  6 months,  a year?  I'm always skeptical on first run guns any manufacturer puts out...

I decided to go ahead an start purchasing equipment to build my SBR upper.  I will wait and see if SIG produces a Patrol version of this rifle (or 5.45x39 version).

I did find that Troy makes a BattleRail for Sig556's, so you could take the 556R and have lots of mounting options for various toys from optics to flashlights.  The problem is that I would want to SBR this rifle as well... and the longer piston system would mean that I would be limited to removing just a few inches of the barrel.

The patrol has (or at least looks to have) a shorter piston system, which makes it perfect for SBRing. So, a 556R Patrol would be an amazing set up to cut down and still be able to slap a suppressor on.

I just got my rifle back from Sig repair and they have modified the lower receiver to fit a steel insert for the entire shelf area along with what I'm pretty sure is a new mag release lever.  Mags lockup tight now, comparable to my AK's.  They also addressed the loose upper / lower fit on my rifle.  The accepted solution here before was to utilize a foam earplug to take up the gap but I felt that was an unacceptable solution.  The upper / lower fit on my rifle is now tight and I look forward to a range session to try it out.

Wow I'd love to see pictures of the mag well area

+1 and keep us updated if you decide to give it another day long beating!

Wow. Sounds like Sig is taking this weapon serious. I'm still torn between a PTR 32 and this. Accuracy is a factor but weight plays a part as well.

What is the weight of the 556R, can anyone tell me?
I know the PTR32 is like 10lbs. unloaded.

7 lbs according to Sig.

I really want Sig to do right with these rifles. I was ready to drop some cash until I saw all of the poor reviews. I'm glad to hear that they are addressing the magwell issues, now they need to focus on reliable extraction and feeding...