Ruger introduced its new SR-556 rifle at last year's National Rifle Association show in Phoenix. The announcement ended years of speculation that Ruger was indeed working on an AR-style rifle, and the SR-556 quickly became the buzz of the show. While the newest Ruger long gun possesses many typical AR features, it also has a Ruger-designed piston drive system. The patent-pending, chrome plated two-stage piston system provides a cleaner, cooler running, and more reliable operation than any standard AR gas impingement system can deliver. Read our full review of Ruger's SR-556 .
Ruger's SR-556 Carbine
What sets the SR-556 apart from any other AR on the market is its piston drive upper. Its design is simple and effective and it works as advertised. When the rifle is fired, gas is bled from the barrel into the gas regulator where it hits the small diameter of the piston. The rifle arrives with three 30-round Magpul PMAG magazines.
In addition to the piston drive upper, the SR-556 possesses a 16-inch, chrome-lined, hammer-forged barrel, a free-floating railed handguard, folding front and rear sights, and other high-end features and accessories. Ruger not only used components of top quality on this rifle, it obviously has done quite a bit of market research to understand what features savvy shooters desire and incorporated those into the SR-556's design.
Cleaning the SR-556 is not much different than any other AR pattern rifle. To remove the gas regulator, push the cam pin from left to right until the detent stops any additional travel. Remove the regulator, regulator detent, and piston by rotating the regulator until the flat lines up with the hook on the gas block. Ruger recommends using a brass brush to clean the piston bore in the gas block. They also recommend cleaning the top of the barrel below the vent in the bottom of the gas block with powder solvent and a toothbrush. The piston and the regulator can also be scrubbed with a powder solvent and toothbrush.
The 16-inch, hammer-forged barrel is chrome lined and features a 1:9-inch twist. The end of the barrel terminates in a bird cage-style flash hider. Unlike the A2-style flash hider, this one is not closed on the bottom and could potentially cause problems for the shooter firing from the prone position over loose dirt or sand. Fortunately, Ruger uses a standard thread, ½-28, and the flash hider is removable. Those wanting to use a more suppressor friendly flash hider will easily be able to switch out this part.
Each SR-556 comes with a nylong carry bag, three magazines and Troy Industries rail covers.
Machined from an aluminum forging, the lower receiver is outfitted with a six-position M4-style collapsing stock and a rubber Hogue pistol grip.
Ruger's SR-556 was tested with Insight Technologies' new Mini Red Dot Sight (MRDS), a lightweight ruggedized reflex sight that mounts to any MIL-STD 1913 rail. Available with both 3.5 MOA (pictured) or 7.0 MOA dot sizes, the sights also possess MOA positive click windage and elevation adjustments. Weighing just 0.85 ounces, the lightweight sight makes it a natural for tactical use. Its top loading battery compartment ensures no change of windage during a battery change. The MRDS uses a single 1632 battery that Insight claims will last up to a year in the automode.
The SR-556's free-floating rail system is manufactured by Troy Industries and is approximately 10 inches long and the bridge between the rifle's upper receiver flat top and the handguard's top rail is in perfect alignment and perfect for those that like to mount their optics far forward.
Ruger's SR-556 offers the option of an optic or flip-up iron sights. The rifle's front sight is pictured.
Troy manufactures the folding front and rear (pictured) sights that are included on the SR-556. A sight adjustment tool is included with the rifle to dial in windage and elevation.