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The SR-556 / AR-556 is an AR-15 style semi-automatic rifle manufactured by U.S. firearms company Sturm, Ruger & Co. The rifle was introduced in 2009 and as a .308 AR-10 variant, the Ruger SR-762.[2] It is one of several 21st-century AR-15 rifles to use gas piston operation (SR-556). In January 2016 Ruger discontinued all SR-556 rifles and introduced a new takedown variant with a lightweight KeyMod handguard.

Ruger SR-556
Ruger SR-556 - Standard Configuration (discontinued)
TypeAR-15 style semi-automatic rifle
Place of originUnited States
Production history
ManufacturerSturm, Ruger & Co.
Specifications (Standard)
Mass3.60 kg (7.94 lb)[1]
Length832 mm (32.75 in) (collapsed)
910 mm (36 in) (extended)[1]
Barrel length409 mm (16.12 in)[1]
Width64 mm (2.5 in)[1]
Height197 mm (7.75 in)[1]

Cartridge5.56 NATO
Barrels1:230 mm (9 in)
ActionGas-operated, rotating bolt
Feed systemSTANAG magazine



The rifle featured a "two-stage" piston mechanism as opposed to the standard direct impingement system of the AR-15. Gas flow is controlled by a four position regulator. Several key parts, such as the short stroke gas piston, gas regulator, and bolt/carrier group are chrome plated. The bolt carrier features an integral lug in place of the AR-15's gas key. The flash hider is similar to Ruger's AC-556 and Mini-14GB.[3]

The rifle includes a number of other manufacturer's parts such as a Troy Industries railed handguard and Samson folding iron sights, a Hogue rubberized pistol grip, and three Magpul PMAG 30-round magazines. The SR-556SC comes with three 10-round magazines and does not have the flash hider or collapsible stock, making it compliant in several states with restrictive rifle laws. The barrel is 409 mm (16.12 in), chrome lined, and features a six groove, right hand, 1:230 mm (9 in) twist.[2] In August 2010, Ruger announced that the rifle would be offered in the 6.8mm Remington SPC cartridge.[4]

Ruger's introduction of the SR-556 was met with some criticism for its high price tag of around US$2,000. Ruger products are usually known for affordability, but the SR-556 is essentially a regular AR-15 albeit with a different, more complicated operating system, unlike cheaper alternatives, like the Smith & Wesson M&P Sport and Sport II model rifles, of which the original Sport model lacked a forward assist and dust cover. The SR-556 was also criticized for its heavier weight than other AR-15s. Ruger addressed these shortcomings by introducing a lighter and less expensive rifle, the SR-556E.[5]

Ruger AR-556Edit

Ruger AR-556
Ruger AR-556
TypeAR-15 style semi-automatic rifle
Place of originUnited States
Production history
ManufacturerSturm, Ruger & Co.
Specifications (Standard)
Mass2.9 kg (6.5 lb)
Length819 mm (32.25 in) (collapsed)
902 mm (35.50 in) (extended)
Barrel length409 mm (16.10 in)
Width64 mm (2.5 in)
Height200 mm (8 in)

Cartridge5.56x45mm/.223 Remington
Barrels1:200 millimetres (8 in)
ActionGas-operated, rotating bolt
Feed system10- or 30-round detachable box magazine

In September 2014, Ruger announced the AR-556, a variant that utilizes traditional direct impingement action, intended to compete with other entry-level AR-15s. It was produced to compete with other AR-15 models, including the Smith & Wesson M&P15 Sport.

In March 2019, the company announced a pistol version with a 10.5 inch barrel, and an SB Tactical stabilizing brace.


See alsoEdit


  1. ^ a b c d e "Ruger SR-556". Sturm, Ruger, and Co., Inc. Archived from the original on 15 January 2013. Retrieved 9 December 2012. Cite uses deprecated parameter |deadurl= (help)
  2. ^ a b Gilbert, Glenn M., Ruger's SR-556: Ready To Run, Right Out Of The Box, American Rifleman, October 2009
  3. ^ Sweeney, Patrick (2010). "The Ruger SR-556". Gun Digest Book of the AR-15. Gun Digest Books. p. 131. ISBN 978-1-4402-1376-2.
  4. ^ "Ruger SR-556 Semi-Auto Rifle Chambered for the 6.8mm SPC Cartridge". Retrieved 17 April 2018.
  5. ^ Cumpston, Mike. "Ruger's SR-556E 5.56mm NATO". Guns. Vol. 51 no. 12. p. 56.

External linksEdit