New SR556 Carbine

[george11c]

Just got a Ruger SR556 Carbine this weekend and also went to the range. Had some trouble with the piston setting on 2 using 55 grain UMC ammo. So I set the piston setting to 3 and it worked fine after that. Setting 2 included failure to extract and not going fully into battery. I am concerned because the manual and other online resources say that 2 should work well with most ammo and UMC is pretty common. Slapped on a Magpul MOE stock. Anyway, here it is:

[GeneFrenkle]

I thought Ruger recommended running it open for a while until it broke in, then it should be dialed back. How do you like the balance on it?

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[gunderwood]

If it's new it may need broken in. UMC is typically underpowered. Remember most of these firearms are optimized around NATO surplus. A setting either way would not bother me at all with cheap, commercial ammo.

[UnderwaterMike]

Nice gun!

[george11c]

I thought Ruger recommended running it open for a while until it broke in, then it should be dialed back. How do you like the balance on it?

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I hope thats the case. otherwise, it may just be the underpowered ammo. The weight feels good. I think it feels similar to my M4 in the army weight wise. However, now something that is pestering me is that many people are talking about bolt carrier tilt wear on the buffer tube and possibly on the upper receiver. I'm pretty sure I have one of the post-fix models but I'm still paranoid about it haha

[38superfan]

I've owned an SR556E model for several months and there have been no major issues with any of the ammo that I've used. The manual describes that brass should eject straight to the side if the piston setting is correct. That being said, I think the 55gr UMC .223 ammo never actually ejected straight to the side. It ejected either forward or to the rear with no FTE or failures to return to battery.

I've also used some Magtech 55gr 5.56 ammo and it worked as the manual had stated and was more accurate. The difference between the two is that the UMC was .223 and the Magtech was 5.56x45. The gun has also performed well with 62gr Lake City 5.56 and 55gr Hornady Steel Match in .223.

There have been no signs of carrier tilt and after about 500 rds, it's one of my favorite rifles that I've ever owned. Call Ruger if you keep having trouble.

[george11c]

38superfan, what piston setting did you have it on when you've shot this types of ammo? The UMC now works fine on piston 2 but will not lock the bolt carrier back once the magazine is depleted. On piston setting 3, it will fire UMC, Wolf, and Tula just fine.

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[george11c]

Also, the not going into full battery was operator error. I rode the bolt forward which the SR556 does not like. So it goes into battery now when I just let go of the charging handle when loading a magazine in.

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[Mindflayer]

That U!C stuff is a bit weak. Also be sure to run it wet.

If you run Russian stuff, you may need to dial it back. My Ruger SR556 will shear the cartridge, which means rod time. I typically save the steel stuff for the Mini 14, FYI.

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[38superfan]

38superfan, what piston setting did you have it on when you've shot this types of ammo? The UMC now works fine on piston 2 but will not lock the bolt carrier back once the magazine is depleted. On piston setting 3, it will fire UMC, Wolf, and Tula just fine.

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I've had the best results with using piston setting "2." As noted above...proper lubrication is key. Here is a good article on AR-15 lubrication from Shield Tactical http://savedrounds.net/2013/08/

Definitely call Ruger if it remains a problem. They have the best customer service in the business.

[george11c]

UPDATE:

Using the tips on how to lubricate the rifle, I went to the range last night and shot xm193, Wolf, and UMC flawlessly on piston setting 2. Needless to say, I love this rifle now. Cleanup was a breeze as always. The only think I am looking out for now is the carrier tilt on the buffer tube. even then though, aren't buffer tubes about 30 dollars to replace usually?

So its sighted in and ready for an optic. I'm thinking an EOTech XPS2

[38superfan]

UPDATE:
The only think I am looking out for now is the carrier tilt on the buffer tube. even then though, aren't buffer tubes about 30 dollars to replace usually?

There's no carrier tilt with the Ruger piston system. There may have been several years ago when the SR556 came out, but it's a carrier tilt free piston system. Enjoy!

Ruger just came out with the SR762 in 762x51 NATO so you'll have to get the big brother eventually!