Ruger SR556C at 10,000 Rounds. A Photo Essay.

[Tokarev]

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 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 to show interested parties what the gun looked like after the 5,000 rounds and can be seen here: https://www.m4carbine.net/showthread...-A-Photo-Essay

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.

Total parts replaced at 10,000 rounds:

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.


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.

[Tokarev]

Here are some gas port comparison photos.

First up is a new(er) SR556 16" barrel that has less than 150 rounds through it.

Leading and trailing edges of the gas port. Note only slight deformation/discoloration so far.





Now the 556C. The leading edge looks about the same (maybe a little worse) but there's a significant difference on the other side.

[Tokarev]

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.

[Tokarev]

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.

[Tokarev]

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.

[Tokarev]

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!



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!

[Kenneth]

That guns looks great. The SR-556 is a rare gun around here and it's nice to see how it's holding up.

Looking forward to how the barrel is holding up.


Sent from my iPhone using Tapatalk

[Ned Christiansen]

I've had several pass through my hands in class but I just learned more about them that in the last two years, very interesting stuff, thanks!

Got any Black Hills or FGMM 77's, or other premium ammo? Would be interesting to see how the grouping goes with some known good-stuff.

[Tokarev]

I've had several pass through my hands in class but I just learned more about them that in the last two years, very interesting stuff, thanks!

Got any Black Hills or FGMM 77's, or other premium ammo? Would be interesting to see how the grouping goes with some known good-stuff.

I have some 69gr FGMM that I'll try as soon as I can. I also have a box or two of the Nosler 77gr BTHP bullets. I'll load up a handful of those and see if there are any stability/accuracy issues with the high round count.

Stability shouldn't be too much of an issue on the newer SR's as I believe Ruger switched over to a 1x8 twist on these rifles now.

[controlledpairs2]

thanks for sharing!