Ruger SR-556 Takedown/Switch-Barrel Semi-Automatic Rifle

by Jeff Quinn

photography by Jeff Quinn & Boge Quinn

July 16th, 2015


Click pictures for a larger version.





Soft padded case.



Gas piston system in handguard.



Adjustable gas regulator.
















It has been more than six years now since Ruger entered the already-crowded AR-15 market with their SR-556 gas piston rifle. Since then, there have been other variations to follow, as well as their successful and affordable AR-556 gas impingement rifle. Now, Ruger has made things really interesting with this latest version of the SR-556; the SR-556 Takedown. What makes this rifle special is that the barrel assembly can be removed quickly, easily, and without tools for compact storage or transport, and can also switch from 5.56x45mm NATO to 300 AAC Blackout with an accessory barrel purchased separately.

Ruger engineers really earned their pay on this design, as the process for removing the barrel from the upper receiver could not be any simpler, yet when attached, the barrel assembly is locked securely in place. To remove the barrel, pull the slider towards the breech, rotate the barrel, and slide forward. To reinstall the barrel, simply slide it into place and rotate. Quick and simple. The adjustable front sight removes with the barrel, and the 300 Blackout accessory barrel also has a front sight installed. There is no need for headspacing the barrel, is it is already set from the factory.

The barrel is chambered to run both 5.56x45mm  NATO and 223 Remington ammunition. The hammer-forged, chrome-lined barrel measures 16.1 inches in length, and is threaded 1/2x28 TPI to accept standard muzzle brakes, flash suppressors, and sound suppressors. The barrel is fitted with a shortened version of Ruger's standard birdcage flash suppressor. Like the others in the SR-556 family, the SR-556 Takedown has a chrome-plated two-stage piston system, along with an adjustable gas regulator, to assure function with any quality of ammunition.


Model Number 5901
Caliber 5.56 NATO / 223 Remington
Stock Black Synthetic, Collapsible
Finish Manganese Phosphate / Hardcoat Anodized
Sights Folding Sights
Height 7.75 inches
Barrel Length 16.1 inches
Overall Length 32.75 - 36 inches
Width 2.5 inches
Weight 7.6 pounds
Twist 1:9 inches, Right-Hand
Grooves 6
Length Of Pull 11.1 - 14.4 inches
Magazine Capacity 30
MSRP as of July 2015 $2049.00 US

Ruger is not putting a standard milspec AR trigger in these rifles, but instead, it comes equipped with Ruger's 452 Elite two-stage trigger, which results in a much better trigger pull than on most AR-style rifles. Thank you. The trigger on this rifle is just about perfect for a multi-purpose AR.

I tested the SR-556 Takedown with a variety of 5.56x45, 223 Remington, and 300 AAC Blackout ammunition. Velocities were recorded at ten feet from the muzzle at an elevation of 541 feet above sea level. Velocities are listed in feet-per-second (FPS). The air temperature hovered around the ninety degree Fahrenheit mark, with ninety-two percent humidity. Bullet weights are listed in grains.

5.56x45 and 223 Remington Ammunition

Ammunition Bullet Weight Velocity
Stryker V-Max 55 2828
Lake City SS109 62 3013
Handload TSX 62 2777
Winchester USA FMJ 62 2812
Buffalo Bore HP 77 2696
Black Hills HP 69 2535
Wolf Gold HP 75 2444

300 AAC Blackout Ammunition

Subsonic Ammunition Bullet Weight Velocity
Remington OTM 220 1022
Supersonic Ammunition Bullet Weight Velocity
Remington OTM 125 2245
Barnes TAC-TX 110 2323

Accuracy was just what I expected from this rifle; excellent. The SR-556 exhibited very good accuracy with both the 5.56x45 barrel as well as the accessory 300 Blackout barrel. My concern, and the bulk of the accuracy work with this rifle, was to determine if the barrel could be removed and reinstalled without degrading the accuracy or changing the point-of-impact. The lockup seems very solid, but to assure myself that the rifle could indeed be disassembled and reassembled without  losing accuracy, I switched repeatedly between the 5.56 and the 300 barrels. I mounted my Leupold Mark 4 atop the receiver, and starting with the 5.56 barrel, fired upon a target at 100 yards distance. Then, without touching the scope settings, I switched barrels and fired the 300 Blackout barrel on the same large target. After five shots, I switched back to the 5.56 barrel, and fired again. I repeated this exercise several times, with the result being a target with two tight groups; one from the 5.56 and the other from the 300.

The Ruger SR-556 Takedown is an excellent rifle, and really different from anything else on the market. The value of getting the rifle disassembled into such a small package for transport or storage will vary with the user. However, even if compact storage is not of primary importance, the ability to switch calibers without changing the entire upper is a great idea. The barrel locks in securely, and loses nothing in accuracy. The Ruger SR-556 takedown comes with rail covers, three thirty-round P-MAG magazines, instructions, lock, and padded case. Like all Ruger firearms, the SR-556 Takedown is built in the USA.    

Check out the Ruger SR-556 Takedown and other Ruger products online at

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

To order the Ruger SR-556 online, click on the Gun Genie at

To order quality 5.56x45, 223 Remington, and 300 AAC Blackout ammunition, go to,,  and

For extra magazines, accessory barrels, and other accessories, go to

Jeff Quinn

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Click pictures for a larger version.





300 AAC Blackout accessory barrel.



Barrel latch.







Flash suppressors: 5.56/223 (top), 300 AAC Blackout (bottom).









Rail covers.