My first look at this rifle came a couple of years ago while we were filming segments for the Ruger Inside And Out television show at Gunsite. Shown to me with warnings of great secrecy, the switch-barrel version of Ruger’s SR-556 was said to have been in development for several years as the engineers and production folks at Ruger worked out the kinks in producing a gas piston, removable barrel rifle. The rifle I was shown then had two barrels, one in 5.56 and the other in .300 Blackout and we had a bit of fun shooting the .300 barrel with a suppressor attached. More recently, this April at FTW Ranch in Texas, Ruger’s Mark Gurney introduced the perfected SR-556TD (TD for takedown) to me and a small group of writers and now Ruger has announced the rifle to the shooting public.
When the SR-556 came out I ended up buying one and have been shooting it without a single malfunction or problem ever since. As a matter of fact, the rifle is so reliable and accurate I frequently use it as a test bed for evaluating optics, ammunition and accessories. I tested the SR-556 CLA, a lighter weight version of the SR-556 and found it too was utterly reliable. I bought that rifle as well but a neighbor later talked me out of it so it got sold over the fence – an entirely legal and civilized transaction here in Arizona I think should be adopted nationwide. Anyway, by now I guess you realize I kind of like these rifles. I only have two complaints. I like to grouse about the crunchy, heavy military grade triggers in these (and most other AR) rifles and because they are gas piston guns they are a bit on the heavy side as compared to some of the lightweight gas impingement ARs. On the other hand, these minor complaints are far outweighed by the accuracy and reliability Ruger has built into these rifles.
If you know about the SR-556 (or read up on it at www.ruger.com) you know just about everything you need to know about this new rifle as well. The specifications, operating instructions and features are the same. The cold hammer forged, chrome lined, 16.1 inch barrel, hard chromed two stage gas piston and bolt group, Mil-Spec six position stock, adjustable, folding iron sights, quad rail forend and oversize Hogue pistol grip are all the same. The rifles ship with three of the excellent Magpul 30 round magazines. The gas piston has four settings, with the factory default setting being “2”, and in my experience the rifles run like clocks on this setting. The barrel is threaded and the flash hider can be removed so various flash hiders, muzzle breaks and suppressors can be installed. Marked “556 NATO 1-9”, the barrel has a hybrid chamber to shoot both 5.56 and .223 Remington ammunition and the barrel twist rate is 1 in 9 inches. The TD ships, broken down, in a very nice carrying case somewhat like the case for the 10-22 Takedown with a couple of pockets for magazines, ammo or accessories and MOLLE attachment points for adding other bags or gear. As a bug-out setup or a rifle to be kept stowed in a vehicle or an airplane, the SR-556TD is “good to go.”
As the rifle comes broken down in the carrying case the first order of business is to put it together. The upper and lower receivers are mated in the usual way with a couple of push-out pins. But now comes the part where you need to read the instructions that ship with the rifle and think about it a bit before attempting to install the barrel. It’s not hard, but you have to do it right and you may get a little frustrated the first couple of times – I did. The trick is to cant the barrel to the right (if you’re looking at it from the muzzle end). Think 1 o’clock instead of straight up 12. Once the barrel is in, it needs to be rotated counterclockwise (back to 12 o’clock) and you might find pushing in on the barrel at the same time helps. To remove the barrel, pull down on what Ruger calls the slider pads on each side of the barrel while turning the barrel back to that 1 o’clock position, then push it forward. If you get this backwards, and try to push the barrel forward before rotating it, no amount of persuasion or cursing will work. Ask me how I know….. (mutter, grumble).
The rifle comes with an adjustable set of flip up sights and I think that may be all you would need if using the rifle for a stow-away piece, and besides, if you add a scope the upper won’t fit in
the pocket designed for it in the carrying bag. I added a scope for accuracy testing, a set-up that usually lives on my SR-556. It’s an excellent Burris 1.5X-6X-40mm XTR (discontinued) with an illuminated ballistic reticle in their P.E.P.R. mount with 30mm rings. After getting the scope re-zeroed at 100 yards I sat down at the bench rest to see how accurate a rifle with a removable barrel can be. After all, removing and re-installing the barrel has got to effect accuracy, right? Well, Ruger’s Mr. Gurney assured me the rifle demonstrated “excellent repeatability” but I had to find out for myself. After singing my fingers on the hot barrel a couple of times I abandoned my initial plan of taking the barrel off and putting it back on every five rounds but I did it enough times to convince myself that I don’t shoot well enough to appreciate any difference in point of impact that might have resulted from the barrel swap. Once that was established I got serious about trying to shoot some three shot groups with various brands of .223 ammo and came up with these best groups at 100 yards:
- Federal American Eagle 50 grain Varmint 0.60”
- Black Hills 75 grain Match HP 0.35”
- Corr Bon 53 grain DPX 0.48”
- Hornady 75 grain BTHP Match 0.68”
- Hornady 55 grain V-Max Varmint Express 0.75”
I also fired five shot groups and can say that all of them, with all the ammunition, stayed in the 1 to 1.5 inch range or smaller. I’ll take these results to mean this rifle shoots.
The trigger on my sample rifle is pretty good – maybe my complaining about military grade AR triggers is working – it is smooth and crisp instead of crunchy and gritty and breaks at just over 8 pounds. It works well for what I think is the intended purpose of this rifle. If you want a better trigger you can get one from Ruger that’s easy to install and will cut the pull weight in half or more. By the time you read this Ruger will also have .300 Blackout replacement barrels available at www.shopruger.com. These barrels will come with two magazines, a complete gas block assembly and a windage and elevation adjustable front sight so you can zero each barrel and be set when you switch them out.
This rifle is a serious technical accomplishment for Ruger and one that should appeal to those wanting a breakdown rifle or one that is multi-caliber capable. It’s an accurate, rock-solid shooting machine and I’m pleased Ruger has been able to bring it to market.
For more information:
www.ruger.com
www.shopruger.com
www.hornady.com
www.black-hills.com
www.federalpremium.com
www.corbon.com
www.burrisoptics.com
About the Author: 
Ed Head is a regular on Shooting Gallery, Gun Stories and Down Range TV. He has worked for almost 30 years in law enforcement, first in the United States Air Force and then with the United States Border Patrol, retiring as a Field Operations Supervisor. During his Border Patrol career, Ed worked in a variety of patrol, investigative and training capacities. Ed has an extensive background as a firearms instructor, having trained thousands, ranging from beginners to police, military and special operations personnel. Having taught at Gunsite for 20 years, Ed first trained there under the world famous shooting school’s founder, Jeff Cooper, then later ran the school as the operations manager for more than five years. Ed lives in Chino Valley, Arizona, where he continues to teach and write.
I learned today that the rifle I tested was actually a pre-production one and that the rifles being sold are a little different than the one I wrote about. Rather than a Ruger stock and Hogue grip, the production rifles have Magpul stocks and grips. Also, the rifles now have a slimmer contour barrel and weigh about a half pound less.
Ed