At long last, I have finally reached the 10,000 round mark with my Ruger SR556C piston driven carbine.  This has taken me quite awhile (much longer than anticipated) but I finally did it.  

The rifle was purchased new when this model was first released back in 2010.  I shot it regularly after I bought it and it took me about a year to get past the initial 5,000 rounds.  

I cleaned and maintained the gun on a routine basis for the first 5,000 rounds.  It was cleaned and oiled after every major range session and kept fairly wet in-between cleanings.  After the initial 5,000 rounds, I gave the gun a more detailed cleaning and started a thread called Ruger SR556C at 5,000 Rounds.  A photo essay.  The thread was posted here on arfcom to show interested parties what the gun looked like after the 5000 rounds, but it has long dropped off into the archives.  As can be seen from the original thread, the gun looked pretty good internally and I noted nothing alarming at that time.

Once I had the carbine cleaned and oiled, I decided to continue shooting it but without any routine cleaning.  I still added oil to the bolt and carrier when things got a little dry but there wasn't any sort of set plan or schedule.  I just added a few drops of whatever oil was handy when I noticed things were getting a little "raspy."

The gun has been used for pretty much every legal purpose at this point.  I've shot it in 3gun competitions, various carbine classes and used the upper on a select-fire lower.  I've shot slow fire for group and I've shot it fast in range drills.  I've gotten it plenty hot and plenty dirty.  Still, I never really abused the gun by intentionally throwing it in the dirt or mud or anything like that but I've not babied it, either.  

As noted in the 5,000 round thread, the carbine has proven itself to be reliable with brass cased ammo but has given me some issues with cheap steel cased Russian ammo.  Silver Bear and Wolf will leave a case stuck in the chamber almost religiously.  Interestingly, Hornady's steel cased training ammo works fine as does 75gr WOLF and the old Golden Tiger 56gr stuff.  I recently had a bolt override malfunction with an old Sanchez GI mag using Federal Fusion, but it only happened once and I reused that same mag afterward with no other issues.  

The carbine has been used mostly on the #2 (middle) gas setting but I did notice that the gun was starting to eject to about the 2:30 or 3:00 position, so I turned the regulator to the #1 (small) setting.  This worked most of the time but the gun would occasionally short stroke--especially when fired in unconventional prone or any position that didn't place my shoulder squarely behind the stock--so I switched it back to the #2 setting.  Had I not messed with the gas setting at all, I doubt I would have ever had any issue.  

Anyway, without further ado, here are the photos.  

Up first are some general photos of the rifle in the dirty condition:



Note that the dust cover detent is gone.  It had been loose on the dust cover for awhile but finally gave up the ghost at about 8,500 rounds.  



Finish is worn off the face of the Geissele trigger.  This has been in the rifle pretty much since Day One.  



Finish worn off the face of the mag release button.



Note the finish wear on the bottom of the bolt catch.



Gas erosion "flash cuts" inside the flash hider.  This is common on AR15 birdcage flash hiders.



And now some photos of the forend and gas parts.  

Note the purplish hue from carbon fouling along the length of the forend.





This is a difficult area to photograph but there are two distinct little bumps of carbon on top of the barrel underneath the gas block.  The Ruger vents gas underneath the block onto the top of the barrel.  The little bumps aren't as big as I've seen them and it is my belief that, once they get to a certain point, the vented gas actually blows away anything above a certain height/size.



Note the gas leakage around the gas regulator.





And now some pictures of the disassembled gas system.

Note the fouling/leakage around the gas regulator.  The regulator was difficult to remove.  I had to stick a small punch through the adjustment/takedown hole and then tap the regulator out with a small hammer.  Once the regulator was out, the piston dumped out easily.  This surprised me.  I assumed the piston would also be hard to remove.



Piston parts removed from the gas block.







Bolt and carrier parts.



Note how clean the tail of the bolt is where it was "sealed" inside the carrier.



Debris on the carrier.  This was mostly localized to the front end of the carrier.  Much of this is accumulated oil/lube.





Tip of the firing pin is flat.  The focus is off here so it looks flatter than it actually was.  Another fairly common sight on well-used AR's.



Barrel extension in bad need of a shave.



Inside the upper.



Receiver bridge on the upper receiver.  Note the slight wear caused by contact from the bolt carrier.



The bolt and extractor.







Now the gas block removed from the barrel.  Not something covered in the owner's manual.  Attempt at your own risk!







Barrel with forend removed.  Note flutes to reduce weight.



Barrel nut and piston transfer rod bushing.



Transfer rod and spring removed from forend.





Inside the lower.

Note the lack of any scuffing or finish wear from "carrier tilt."





Parts after cleaning.

Note the slight wear on the shaft of the POF roller cam pin.  This is not a stock Ruger part but has been inside the gun pretty much since the get-go.



Bolt parts ready for re-assembly.



Firing pin retainer.



Gas parts ready to go back into the carbine.



Barrel extension after some work with a GI chamber brush and a small screwdriver.



Assembled barrel and forend.  No more fuzzy bumps under the gas block.



Wear to the lower receiver bridge from charging handle.



Wear and "cam pin drag" inside the upper receiver.



And the carbine cleaned and assembled.  Ready for the next 5,000!



Total parts replaced:

Firing pin--tip flattened on original
Firing pin retainer--original was slightly bent and misshapen
Ejection port cover--broken
Extractor spring--precautionary measure
Magazine release--precautionary measure.  The original was working fine but I noticed the shaft was slightly loose on the bar that interfaces with the magazine.  

Next up will be to get the gun out to the 100yd range and put it on paper with a few different brands/types of ammo.  It has always been a solid 2MOA shooter and I'm curious to see how it shoots now that it has 10,000 rounds down the pipe.

There you have it.  The whole event was fairly anticlimactic.  Thanks for looking!

Thanks for sharing.

good job man! 10,000 rounds is a good time no matter what.

was that the first time the gas regulator plug had been removed?

First time it has been removed in 5,000 rounds.  I was a little worried that I might have to soak/douse the gas parts in solvent but the regulator came out without too much force.  

Great post. I own a pof since 2009. I though about selling my upper but then I decide to keep it since this was my first AR purchase. Hope u get to 20k soon. I'll follow this.

Great post, since I'm considering purchasing a SR556 would purchase it again?

Yep.  Without hesitation.

My only complaint with the gun is that it is somewhat heavy even with the fluted barrel.  But that shouldn't be an issue now because Ruger is using a lighter profile barrel on the SR556TD.

Thanks so much for this thread. Love seeing stuff that gets used. Never have felt the urge for piston guns but it is great to see the ones that have been around a while are all sorted out. Ruger really makes solid products in my experience.

The weight you mentioned has always been one of the biggest drawbacks to the piston systems in my opinion. Although plenty of DI guns are fat pigs as well. I have a Rock River midlength that will probably never get shot again because of how heavy it is.

The SR556C, as pictured above, has been dropped from the Ruger product line and has been replaced with the SR556TD.  But, from what I remember, the published weight was 7.8 pounds.  But even with the fluted barrel the carbine is still quite nose heavy.

The new SR556TD with the quick detach barrel drops the weight to a published 7.1 pounds.  This makes for a much better balanced rifle in my opinion.  It is what Ruger should have been using in the 556 series for the start.  

Thanks for sharing your update!  I'm only a bit over 3,000 rounds through my SR-556E, but it's been stone cold reliable as well.

Very cool post. Glad to see Piston rifles holding up well!

Great post, thanks for sharing!  It's nice to see the POF roller cam pin holding up well.

Here is a short YouTube video a buddy took for me using his bore scope. Note what looks like charcoal. That used to be rifling!

I have a couple still photos of the throat and gas port on my 556C and another Ruger with less than 200 rounds through it. I'll get them hosted and posted shortly.



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i might be a little slow here but are you saying that was a ruger with 200 rounds thru it with worn out rifling?

The video above is showing the throat of my 556C.

The still photos that I will post shortly are comparisons of a relatively new gun vs mine.

Love my Ruger AR ! I am up to 7k on mine it just keeps ticking.  I have the model that has the slimmer rail which I really like. eats any ammo cept steel, they seem to stick in chamber between firing strings and have to be tapped out.

Great post!!  Awesome to see what a well used gun looks like inside and out.  I commend you sir!

Well that barrel is toast.

Maybe but I'm guessing it'll still shoot pretty well.  I'm still hoping to get out one of these evenings and put the gun on paper at 100 yards.

Here's a video of the crown.  It actually looks good.  Note the step where the barrel ends and the integrally machined flash hider begins.

IN for the range report

Thank you for your very good report.

Oh it's still a serviceable barrel, no doubt. I was talking about in terms of precision over 100 yards.
However, perhaps I spoke too soon. I too would be interested in seeing what kind of groups it can hold with standard mil ball with its current round count.

Nice write up. Thanks for posting that.

Thanks for the report.  If you had better lighting and no flash it would be easier to see the minute details you're pointing out.

Thanks for posting.

Nice range report thanks.

Very cool.  Made for some good reading.

In for range report

I finally managed to get out to the range.  I took the Ruger and another rifle to use as my control sample.  The "control sample" is one of the Ruger AR556 direct impingement rifles.  It has had the factory barrel replaced with a lightweight 1x7 twist barrel from Ballistic Advantage.  Both Rugers have Aimpoint 2MOA optics mounted.  

I used the same method for both rifles.  First, I confirmed and/or adjusted zero at 50 yards from the seated position by firing three rounds center mass on a humanoid silhouette.  I then moved back to 100 yards and fired five rounds of each type of ammo from the prone.  I walked downrange and marked each group as it was fired.  I tested both rifles with Federal Fusion, Federal 69gr Gold Medal and IMI 77gr Razor ammo.  

First up is the overall of the SR556C target after all rounds were fired.  



And here's my Ballistic Advantage target for comparison.  



First up from 100 yards was the Federal Fusion.  My first group with the SR556C was low and left so I made an adjustment and fired a second group at 50.  This put me high and right on the target at 100 yards.  



And here's the Federal Fusion from the BA barrel.



Next is the Gold Medal from both guns after making an adjustment to the SR556C's zero.





Then I finished off both guns with the 77gr stuff.  Both rifles seemed to prefer this over the other brands/weights.  Or maybe I was finally getting warmed up.  Either way the 77gr seemed to shoot the best.  

This was a very nice group with the SR556C.  It would have been spectacular without the one high flier that went into the 69 GMM group.



And the 77gr stuff from the BA barrel.



So there it is.  The old gun still seems to shoot about as well as it ever did.  Granted, I could squeeze more accuracy out of either gun with a magnified optic and/or a target more conducive to slow aimed fire.  

That's good stuff. What's next?

I'll try to get some additional accuracy results sooner rather than later.  I need to see if I can't pull a scope off another rifle and stick it on the Ruger.  See what I can do with a little magnification.

Otherwise, I guess I'll just keep on shooting the gun.  I wonder what it'll look like at 15,000 rounds.

Thanks for this, very few people ever put 10K through their rifle ever.

Great write up, sir!  Still loving both of my SR-556 rifles and this report just reinforces the excellence  of the platform!

Very nice write up.

Thank you for this information.
I have Adams upper on Aero lower, they will never see 5k.

I just put a Kynshot hydraulic buffer in. Initial testing shows thatvthe gun will no longer fully cycle on the small gas setting. Also the cyclic rate is slightly slower on full-auto.

More messing around is in order but initial results are favorable.

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Hey Melvin, how many rounds would you say you shot through this upper while on the registered lower in full auto?  It would be very interesting to measure the barrel wear on another 556C with as high of a round count but none of them in full auto to compare the differences in barrel wear.  Thanks for a great write up.

Great write-up OP!

I never really tracked my usage on a full-auto lower but it is probably somewhere around 1,000 rounds over the course of these years. Plus I've sent quite a few mags downrange via bumpfire. LOL.

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Thanks Melvin

No interest in this rifle, but I just wanted to say the author did a fantastic job reviewing this rifle. Excellent details. My guess is most current piston ARs could handle this test quite quite well.

Thanks for reading.

I think you're right that many of the available piston guns (and DI as well) would make it through a similar shooting regimen. If I had time, ammo and money I'd love to long-term a few more.

Anyway, I am pleased to see the Ruger make it this far and beyond. There were many on the various boards who were convinced the Ruger was a flawed design that would suffer from broken bolts and broken transfer rods.

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Good read for sure thanks for posting it.  I kick myself for not buying one of these when I worked for Ruger.  I was there to see the prototypes before the public knew about them and we were offered them at ridiculously low prices when they became available.

Thanks for the updates!
I have a 556E that I've had since July 2013.
I use it for 3 Gun and training.
I'm about 4000 on the round count.
I run it reasonably hard, don't baby it at all and it just keeps on ticking.
I replaced the above average milspec trigger with an excellent Wilson Combat Single Stage trigger.
Like you I'm getting about 2MOA with a red dot.

Only slight negative was the weight.
I bulked up, got stronger (a good thing) so the weight is no longer an issue.
I can run and gun with it all day, easy.

It's been a fun rifle to own, easy to maintain and 100% reliable.
http://i269.photobucket.com/albums/jj78/supertanker_photos/DSC03552_zps6d0e26c1.jpg

Thank you for sharing your experiences with the SR556. Certainly seems to be a solid gun. I kind of miss seeing Newport, NH on the receivers for these and the SR762.

I really have wanted to get an SR762, but two things are holding me back (other than it being reasonably, but not outrageously, expensive). One, I've been waiting to see if there was going to be a big brother DI AR companion to the AR556 a year or so after its release, and thus far we haven't seen this. Two, in the back of my mind I have a nagging worry about whether either the SR 556 or 762 piston guns will continue to be produced 6 or 8 years from now. The 556 has been around for about 8 years or so (albeit its now only available as the takedown model) so its been out a while for sure, but it'd be really crappy to get one of these, however good it might be, and then find out down the road 4 or 5 years that your really great gun with its largely proprietary piston parts is now discontinued.

I liked the "E" and wish Ruger still made a version of it.  It was about the only factory piston option around that was under a Grand.