Ruger SR556

I know it didn’t just come out, but…

http://vuurwapenblog.com/2010/07/21/ruger-sr-556/

http://vuurwapenblog.com/2010/07/23/ruger-sr-556-range-update/

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I’m going to be honest. I would probably never purchase this rifle. It just has too many drawbacks, in my mind - it’s heavy, it has an extreme forward CG, it’s not fully end user serviceable, you’re effectively limited to one rail system, and it’s a gas piston/op-rod weapon. These are the items that came to mind when I first examined an SR-556 at the 2009 NRA show in Phoenix.

Evidently, Ruger heard enough about weight from customers that they recently introduced the SR556C model, which has a shorter, fluted barrel, resulting in a significant weight savings. Unfortunately, it also has an integral muzzle device; this severely limits the options of the end user, and it’s nothing that I’d want to deal with. Some may be perfectly happy with it - more power to them. It’s just something that makes me scratch my head and wonder, “What were they thinking?” It’s good that they listened to consumer demand regarding weight, though.

You’re probably asking yourself why I bothered with this rifle, given the previous few paragraphs. Well, although I had shot one, I had not owned one, and I figured that it would make for an interesting comparison with the POF P-415 I have for T&E. In addition, a major reason for acquiring it (in a trade, I should add) was to determine the center of gravity of the weapon, and add it to my weight and balance calculators. I’ll get to that later. First, an overview of the weapon.

Overview

The SR-556 includes a number of nice extras. A decent soft case, three Magpul PMags, the aforementioned Troy rail, Ruger marked Troy front and rear folding iron sights, three rail covers, and a Hogue grip are the items that immediately come to mind.

The supplied stock is modeled after the Colt M4 stock body, with minor differences in construction that cause it to weigh approximately 1 ounce more than the M4 stock. I found it wholly inadequate for the purposes of balancing out the muzzle-heavy weapon, so I immediately installed a Vltor EMod. Any decent “fighting rifle” will have a white light, so on went a spare Surefire G2 with drop in LED, and I also added an EOTech XPS 2-0. With these items, the three rail covers, and a 30 round PMag loaded with 55gr ammunition, the weapon weighed in at almost 10 pounds 8 ounces. I should add that the XPS is less than 2 ounces heavier than an Aimpoint T-1 Micro in a LaRue mount, so if you want an optic and a light on your SR556, you’re going to be staring at 10 pounds loaded even without a heavier stock.

While swapping out the stocks, I checked the receiver extension tube to see if it was straight. Like every other SR556 I’ve examined, it was not. This is easily avoided during assembly - the tube needs to be held straight while the castle nut is being tightened, or the tube will turn with the nut. This really will have no effect on the function of the weapon, but it provides some insight on assembly and QC practices.

Ruger SR-556s are test fired with a full 30 round magazine. This is a test regimen I wholeheartedly approve of, and wish more manufacturers would follow.

This is the wear on the receiver extension tube after test firing. It is similar to the wear my Ares converted AR exhibited after a similar round count. Like the Ares weapon, the receiver endplate has not been staked to prevent nut rotation; so far, unlike the Ares weapon, carrier impacts on the tube have not caused the nut to come loose, allowing the stock to rotate and the weapon to become nonfunctional. There is no excuse for any hard-use AR - but especially for a piston/op-rod AR - to not have this item staked.

Ruger is a recognized industry leader in investment casting, and it’s my understanding that they make their own fire control group parts. This can be a mixed blessing, but the trigger pull is quite good for a stock trigger, with little to no grit. Unlike other manufacturers, Ruger does not put grease on the fire control group contact points.

Ruger utilizes a notched hammer and a non-shrouded firing pin carrier. Should the disconnector fail, these items will hang up on one another, causing the weapon to become completely nonfunctional. This is fine as a safety feature to make lawyers happy, but is not preferable for a weapon that one might stake their life on.

Moving to the front of the weapon, we see the Ruger muzzle device, similar to those used on Mini-14 variants. The barrel, as many know, is hammer forged 41V45, chrome lined, with a 1/9 twist rate. The profile can only be described as very heavy. The gas port is forward of the standard midlength location, and the massive gas block is pinned with two massive pins that were pressed in with a massive press. These pins are the reason why the weapon is not completely user-serviceable (although Adco Firearms tells me that they can remove the gas block without any problems, allowing them to reprofile or flute/dimple the barrel - normal disassembly rates apply). The gas regulator is easily adjustable with the mouth of a cartridge case or other such object, but seems very resistant to unintended rotation. It offers four positions, from “no gas” to “full gas”.

The bolt carrier group has been completely hard chromed, with the exception of minor pins and the ejector. It weighs in at 11.1 ounces, the same as the lightest of AR-15 bolt carrier groups. For the sake of comparison, the POF P-415 bolt carrier group is 11.4 ounces, and a standard M16 carrier group is 11.5 ounces.

Though the extractor spring did not appear to be as large or have as much oomph as the Bravo Company extractor springs offered in their upgrade kits, it did have an o-ring installed.

Function

Side note - A friend of mine is a gunsmith for a major firearm retailer, and he tells me that he’s had 5 Ruger SR556s returned for functional issues. When he tested them, only one of the five actually exhibited problems - failures to extract with Wolf. Given the appearance of the extractor spring, I’m not completely surprised. As for the other four, maybe the owners decided that they just didn’t like the weapon. If so, that’s a pretty crappy way to deal with it. Don’t lie to a dealer in order to get a full refund on a used product that works fine.

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Today I made it to the range with the SR-556. I had 6 other rifles to shoot, so the total round count was limited, but I started to get a better feel for how the weapon handled.

I was in luck - also at the range was Mike Pannone of CTT Solutions and Viking Tactics. An all-around good guy, Mike seems always willing to take a minute (or an hour) to help me with my shooting technique. Today, he ran me through a drill he was working on for the Border Patrol agents that he’s paid to train - two shots to the chest and one to the head of a silhouette at 20 meters, two shots at an IPSC A zone steel plate at 50 meters, then two to the chest and one to the head of the silhouette again, and finally back to the steel plate for 2 more hits.

My times with the Ruger SR-556 and an EOTech were in the 10.5 second range, though I was consistently missing shots on the steel plate at 50 meters. Shooting his own AR, Mike was in the low 6 second range - he said an 8 second run was, for him, “slow”. Note that the EOTech XPS2-0, my time with it having expired, has been replaced with my well-used 552 on a LaRue LT-110 riser.

Below, I run through the drill with a BCM lightweight midlength. The steel plate is the black dot to the left of the silhouette. With the BCM (equipped with a TA33 ACOG), my times were in the high 8s to high 9s - no misses. Although the magnified optic certainly helped, it took a little time to get used to the extra weight out at the front of the Ruger, and I kept “overshooting” as I switched from target to target, which led to frustration, wailing, and gnashing of teeth on my part.

I did not bother with accuracy testing after zeroing the optic, though the weapon seemed consistent enough for the task at hand. Later, I shot the drill once more with the Ruger. It was a “clean” run - no misses - and although the timer was not available, the pace was similar to my earlier ~10-11 second runs. I should add that Mike Pannone considers a 10.2 second “clean” time to be average for the shooters he was training.

Recoil is quite mild - as one might expect from a 10.5lb AR-15 with a rubber buttpad shooting .223 American Eagle. Still, recoil characteristics are not ideal, and the weapon exhibited a little more muzzle rise than I expected. As you can see in the first picture of this review, fired cases were ejected between 4 and 5 o’clock - more to the rear than I’m used to. I left the weapon on setting 2 for the day, and experienced no malfunctions. My only functional complaint - if I really wanted to get nit-picky - was that the selector was stiff when going from “fire” to “safe”, but not “safe” to “fire”.

After that last drill, I tried holding the rifle at the ready for as long as I could - after only a few minutes, my arm became quite sore. Unlike a lightweight standard AR, which I feel that I could hold at the ready or low ready for a very long time, the SR556 was just too much for my weak limbs to hold up all day.

My initial impression of this weapon is that it is a decent firearm - it functions, and it puts the bullets where you want them to go. If you are willing to train with this weapon and this weapon alone - or its SR-556C brother - you will probably do quite well with it (them), and be happy with the performance of the weapon(s). However, as an AR-15, for my intended use, it is not exactly satisfactory. Its handling characteristics are so different than a “standard” AR-15 that I would find it disconcerting to go back and forth between the two, or at least, I would personally have a fairly steep learning curve every time I switched. It is also unsuited for comfortable all-day carry, such as when hunting or backpacking.

I would like to thank Mike Pannone for taking a good chunk of time out of his busy day to help me out with my shooting yet again. If you get the chance to take a class taught by him, don’t miss out.

Nice review. I looked at one when they were released and promptly purchased a BCM carbine. The weight, proprietary parts, 1/9 twist etc didn’t,IMHO, warrant the price tag.

Nice review. I was intrigued when it first came out, but got smart for the reasons you pointed out above.

All the ones I’ve handled have disproportionately heavy, including the SR-556C. My 6940 with optic and light is a pig, but it feels light compared to the Ruger, out of the box.

Great review! I needed that info for a friend. Thanks

Appreciate your fair and unbiased review. I’ve personally become so jaded against these things that I couldn’t possibly have posted something as impartial as you did. So kudos, you make a good journalist type guy :).

All that said, for the way Ruger markets these guns that Bolt Carrier is inexcusable.

I was looking forward to this rifle, until I handled it at the SHOT show here in Phx. Now with your review and looking at the BCG, Im even more put off by it.

I’ve shot the Ruger variants, and agree, from the specific standpoint of how the recoil impulse carries bacward. I felt that the recoil as a whole has three distinct impulses that combine into the entire impulse. Every shot had…and I literally can’t think of a better way to characterize it…a “cl-cl-clink!” aspect. Almost as though there’s significant gaps between piston, rod and carrier and that the shooter (me, in this case) is feeling the impact of gap/gap/buffer.

Didn’t like it one bit, and it kicked me off to the right, regardless of shooting position whereas other piston guns do not. I freely admit to not knowing how that might come about, or if adjusting the setting on the gas block would do away with it or not.

Is your experience in any way similar, or did it feel different to you?

Yes, that’s a good description. It wasn’t sharp like some other piston weapons, but I still came off the target in an unfamiliar manner. The first thought that popped into my head after I fired a round through it was “Well…that was different.”

This is part of the reason why I’m trying to get a digital force gauge in order to “map” the recoil impulse of various weapons.

I haven’t shot it on the other settings yet, but I will do so tomorrow, and pay careful attention to how it behaves.

Good review. Ruger’s fan base might be quite happy with this gun.

I run into more shooters who don’t know dick, than shooters who can give a good critical evaluation of a weapon. I guess that’s why so many bad guns and foolish gadgets are sold every day. :frowning:

Thanks for the great review. I first found out about this site after I purchased the Ruger SR556C that I have now. Since purchasing it I have made some changes to the rifle. I replaced the trigger with a Geisselle SSA trigger switched out the stock for a UBR stock, add a Troy Stubby verticle grip and then put in a Eotech 553 site. I totally agree that the weapon is heavy. Too heavy!

I guess I’m one of those shooters, as markm states, “I run into more shooters who don’t know dick”. I’m not using this quote to point a finger or start anything but as far as this weapon is concerned right now I like what I have. Maybe once I learn more and shoot this particular weapon more and run it through some classes I may better learn it’s limitations and or good qualities. So far I already know it is way too heavy. I have put close to a thousand rounds through it and it shoots well and even just as accurate with Hornady 75gr Tap ammo as anything else I have shot.

If I do anything it may be to purchase a complete upper from another manufacuterer and swap that out with the Ruger upper. Or as I learn more I may just build a weapon from the ground up. For now though I guess not knowing dick(ignorance) is bliss.

for the 14.5" version they fluted the barrel under the rails to lower the weight by half a pound. It was a heavy barrel before. Not sure if they applied this to the 16" models recently.

Where do you find the “c” version.

…and with the various flaws mentioned, does the piston system make the rifle more reliable than the typical AR?

The BCG might be flawed, but does the cleaner running system make up for this? Said another way, does a well used, and uncleaned Ruger perform more reliably than an AR?

BF

Where do you find the “c” version.

Here is Ruger’s Official Data sheet.

…and with the various flaws mentioned, does the piston system make the rifle more reliable than the typical AR?

The BCG might be flawed, but does the cleaner running system make up for this? Said another way, does a well used, and uncleaned Ruger perform more reliably than an AR?

I’ll make this brief because it’s been done to death on this forum and if you want explanations to the whys of the situation you can use the search function to look up past threads on the subject.

Except for VERY specific circumstances (i.e. a lot of full auto fire in a less than 14" barrel rifle WITH a supressor attached) piston systems do NOT demonstrably improve AR reliability. ARs being properly built improve AR reliability: this means proper chambers, bolts, carriers, gas tubes and ports, receivers, feedramps, springs and so on are the key to success, not sticking unnecessary crap in the frontend of your gun. Therefore, a Colt, FN, DD, BCM, Noveske, Spikes, etc direct impingement gun with a non-garbage bolt carrier and other details paid attention will be a damn sight better in the reliability department than this monstrosity. Moreover, Rugers in particular have developed a reputation for chronic “carrier tilt”, or the proclivity of the bolt carrier to grind against the receiver under recoil. So not only is a Ruger piston gun less reliable than a proper DI gun, it’s also literally tearing itself apart.

Finally. Pistons are NOT cleaner, they just dump their gasses at the front (ahead of the piston and… oh by the way, where your sights, lights, and hands are) instead of out the ejection port. Either way those gasses don’t go away and piston users have to deal with the special problem that enough soot can build up to jam the piston, ceasing operation of the gun (better piston designs take measures to reduce this problem significantly, Ruger isn’t one of them).

I’d take a Ruger over crap DI ARs from Bushmaster, DPMS, CMMG, Doublestar, etc but if you look around this site, you’ll see a lot of folks who put 10,000-20,000 rounds per year on their ARs, many of whom have had to use their weapons in real life combat operations, and you would do well to notice that 98%+ of them aren’t running any kind of piston AR in 5.56*, much less a Ruger.

*and the ones that are are running LMT MRPs because they can quick-change barrels, not because they believe pistons give them a reliability boost

We had a Ruger SR556 in a recent class. It seemed to run very well once lubed properly.

the SR556C is .5lb lighter according to the website, they need to apply the fluting they did to the heavy barrel to lower the weight on the 16" version. Its front heavy

This comes from not using a milspec (Colt) nut, backplate, and buffer tube.

Too much slop in the parts and then they bind up causing the buffer tube to rotate during assembly.

Recoil comparison video

Thanks for the video, it really highlights how much the SR-556 deviates from other ARs under recoil.

OK I just had a deal breaker with my Ruger 556c. I’m taking a class in a couple of months and tried to order a complete BCG. Ruger said no. The only thing I could do is send the rifle back in and they would replace whatever happened to break. I could not order any spare parts for myself. No BCG or piston parts period.

My only complaint with the rifle before this was the weight. However, not being able to order spare parts, when every other manufacturer will allow this, or even being able to drop in aftermarket BCG’s etc is not something I want to contend with. Rifle is on the way out the door.

Any suggestions? $1500 is my budget. Would like it to come pretty much complete, not basic, so that all I need to do is transfer optics.