Ruger’s New SR-556E Semi-Automatic 5.56x45mm Rifle


by Jeff Quinn

photography by Jeff Quinn & Boge Quinn

May 27th, 2011


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Ruger's new SR-556E rifle with Leupold's new VX-R HOG scope.



Four-position gas regulator.





Top to bottom: forward assist, empty case deflector, magazine release, safety switch, bolt release.



Slim aluminum handguard with full-length Picatinny rail on top is drilled for accessory rails sold at



Removable AC-556 flash suppressor.





It has been just slightly over two years now since Ruger introduced their rendering of what an AR-15 rifle should be. The heart of the SR-556 rifle is its simple, rugged, and reliable gas piston system. A gas piston in an AR is what many shooters want; Ruger delivered, and delivered at a price that is very competitive for a quality, American-made gas piston system on a top-tier AR.

Ruger held nothing back with the introduction of the SR-556, outfitting the weapon with top quality components, such as a Troy Industries quad rail, along with the excellent Troy folding sights. While these are very nice features, quality costs money, and the rail and sights add substantially to the cost of the SR-556. The only complaint that I have heard about the SR-556 is that some shooters balk at the price, comparing the price of the SR-556 with low-end gas-impingement systems. When comparing the price of the Ruger against other top quality piston guns, the Ruger competes very well, but still, many shooters do not want or need a quad rail, and can do without folding sights, as most will mount an optical sight anyway. For those, Ruger has just introduced the SR-556E, eliminating the sights and quad rail, with a suggested retail price that is, at the time of this writing, $1369 US, which is $626 lower than the price of the other four versions of the excellent Ruger SR-556.

Having now to compare the new SR-556E to the previous versions, we will look at just what a shooter has to give up to save that substantial difference in money. First, as noted above, the 556E eliminates the Troy sights. To me, that is no big deal. I seldom if ever use mechanical sights on an AR, preferring greatly to use a modern, high-quality scope or other optical sight. Even at close range, I prefer the fast target acquisition offered by a good, low power or no-power optical sight, as do most who use ARs for serious purposes, such as our nation’s military men and women. In Afghanistan and Iraq, most soldiers and Marines prefer a good optical sight such as the ACOG, which makes it easier and faster for them to hit their targets, compared to the mechanical sights on an M4 carbine or M16 rifle.

The other versions of the SR-556 wear the quad-rail hand guard, which is an excellent unit, and provides lots of Picatinny rail for mounting various accessories to the rifle. However, I greatly prefer the slimmer, sleeker hand guard on this new 556E. The clean hand guard feels much better to my hand, and is reminiscent of the slender fore ends offered on some of the German G3 and HK rifles. The 556E hand guard is a very good unit, made of aluminum, almost eleven inches long, but barely over one and one-half inches across, and feels great in my hand. The hand guard still wears a full-length Picatinny rail on top, and the two sides and bottom are drilled and tapped to accept bolt-on sections of Picatinny rail as need. This allows the rifle’s owner to add on rail as needed, if needed, to suit his particular desires. It is a very good system, and eliminates the need for rail covers. The Picatinny rail sections can be purchased individually from I love the new hand guard.

Instead of three thirty-round P-Mags, the 556E ships with only one, helping to lower the cost a bit, and allowing the owner to spend his money on whatever magazines he prefers. One of the endearing traits of the AR-15 rifle system is that magazines are cheap and plentiful. Weighing in at only seven pounds, six ounces, the 556E balances very well. The overall length is adjustable from 32.75 to 36 inches, with its six-position buttstock.

The Ruger SR-556E uses the same reliable, chrome-plated two-stage gas piston system that runs the other SR-556 rifles. It still comes with a six-position telescoping buttstock, and is made from the same high-quality materials as are the other SR-556 rifles. The SR-556 barrel is not chrome lined, but is the same high-quality hammer-forged mil-spec 41V45 barrel that goes on the other SR-556 rifles. The barrel measures .807 inches inside the hand guard, and .698 forward of the gas block, which also has a Picatinny rail machined into the top. The 556E has the AC-556 style birdcage flash suppressor, and is removable to attach other accessories such as muzzle brakes and sound suppressors.

For accuracy testing, I mounted my mule, the Leupold Mark 4 8.5 to 25 power target scope using an ArmaLite one-piece mount. Velocity testing was done with the chronograph set out twelve feet from the muzzle at an elevation of 541 feet above sea level, approximately. Temperatures hovered around the sixty-five degree Fahrenheit mark during all testing. Velocity readings are the average of several shots fired, and the results are listed in the chart below. Velocity readings are listed in feet-per-second (fps). Bullet weights are listed in grains. FMJ is a full metal jacket bullet. HP is hollowpoint. SRT is a load using specialized bullets as loaded into ammo produced by Extreme Shock Ammunition. V-Max is a polymer-tipped varmint bullet. TSX is a Barnes Triple Shock homogenous copper hollowpoint bullet. The handload listed uses the TSX bullet with 24.5 grains of Ramshot TAC powder, a Remington small rifle primer, and Winchester commercial .223 Remington cases.

Ammunition Bullet Weight Velocity Accuracy
Stryker V-Max 55 2831 1.06"
Lake City SS109 62 3001 2.40"
Hand Load TSX 62 2760 1.19"
Winchester USA FMJ 62 2829 1.89"
Buffalo Bore HP 77 2692 0.63"
Extreme Shock SRT 55 2412 1.92"
Black Hills HP 69 2525 0.75"
Wolf Gold HP 75 2451 1.19"

Accuracy was very good from the SR-556E rifle. I tested it bench-rested over a Target Shooting Model 500 rifle rest, with the results shown in the chart above. As expected, Buffalo Bore Sniper ammo turned in the best accuracy, followed closely by the Black Hills Match and Stryker from The American Marksman. The rifle’s one-in-nine-inch twist stabilized the 77 grain bullet from the Buffalo Bore load very well, despite “experts” stating that a faster twist must be used.

After completing the accuracy tests, I mounted the new Leupold VX-R Hog scope atop the Ruger’s Picatinny rail, and proceeded with velocity and function testing. I love that scope. Marketed as a hunting scope, it is also a superb tactical scope as well. Very versatile, with outstanding optical quality.

Functioning was one hundred percent reliable with every brand and type of ammunition tested. The SR-556E fed, fired, and ejected every round perfectly. Ejection was straight out to the right, with the empty cases landing about six feet from the shooter. Shooting left-handed as I do caused no problem at all.

The Ruger SR-556E is my favorite so far of the Ruger SR-556 series. I like the slim hand guard better than the quad rail. The SR-556E rifle is an excellent gas piston carbine. The SR-556E ships in a soft-sided padded zippered carry case, and comes with a padlock, instruction manual, and one magazine. While costing several hundred dollars less, the SR-556E is built with the same quality and care as the other SR-556 rifles, and is built in the USA.

Check out the extensive line of Ruger firearms and accessories online at

To order accessory rails, magazines, and sights for the SR-556E, go to

For the location of a Ruger dealer near you, click on the DEALER LOCATOR at

To order the SR-556E online, go to

To order high quality 5.56mm and 223 Remington ammunition, go to,, and

For a look at the complete line of Leupold scopes and other optics, go to

Jeff Quinn

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Click pictures for a larger version.


SR-556E comes with zippered soft padded case...



...and one thirty-round P-Mag.





Six-position telescoping buttstock.



Bolt and carrier have a black oxide finish.



The SR-556E was very accurate, and 100% reliable, with a variety of ammunition.