Ruger SR-556 - Standard Configuration (discontinued)
|Place of origin||United States|
|Manufacturer||Sturm, Ruger & Company, Inc.|
|Weight||3.60 kg (7.94 lb)|
|Length||832 mm (32.75 in) (collapsed)
910 mm (36 in) (extended)
|Barrel length||409 mm (16.12 in)|
|Width||64 mm (2.5 in)|
|Height||197 mm (7.75 in)|
|Cartridge||6.8mm Remington SPC (upper only)|
|Barrels||1:230 millimetres (9 in) Right Hand twist|
|Action||Gas-operated, rotating bolt|
|Feed system||STANAG magazine|
|Sights||Folding Iron Sight|
The SR-556 is a semi-automatic rifle carbine manufactured by U.S. firearms company Sturm, Ruger & Company, Inc. The rifle was introduced in 2009, marking Ruger's entry into the popular AR-15 market, and it would continue with a .308 AR-10 variant, the Ruger SR-762. It is one of several new AR-15 rifles to use gas piston operation. In January 2016 Ruger discontinued all SR-556 rifles and introduced a new takedown variant with a lightweight KeyMod handguard.
The rifle features a patent-pending, "two stage" piston mechanism as opposed to the standard AR-15 direct impingement system. 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.
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 millimetres (16.12 in), chrome lined, and features a six groove, right hand, 1:230 millimetres (9 in) twist.
- SR-556FB, standard model (discontinued)
- SR-556SC, state compliant (discontinued)
- SR-556C, carbine (discontinued)
- SR-556CLA, carbine lightweight adaptable (discontinued)
- SR-556E, essential (discontinued)
- SR-556ESC, essential state compliant (discontinued)
- SR-556VT, varmint (discontinued)
- SR-556/6.8, 6.8 SPC (discontinued)
- SR-556TD, takedown (originally with a quad rail handguard and a 1:9 RH twist barrel; currently with a KeyMod handguard and a 1:8 RH twist barrel)
- AR-556, M4-style direct impingement model, (in production since 2014)
- AR-556 MPR, Multi Purpose Rifle, (in production since 2017)
On September 29, 2014 Ruger announced the AR-556, a variant that utilizes traditional direct impingement action and introduces a rear flip up sight similar to the Magpul BUIS. Pricing suggests that it's intended to compete with other entry level AR-15s.
Specs: Stock - Black synthetic collapsible Front sight - Adjustable post Rear sight - Adjustable Ruger Rapid Deploy---Registered trademark Barrel Length - 16.10 Thread pattern - 1/2"-28 Handguard - glass filled nylon Twist - 1:8"RF Finish - Type III Hard Coat Anodized Height - 8" Weight - 6.5LB Suggested Retail - $799.00 
Three State Compliant models were later introduced, one with a fixed stock, one with a fixed stock and no muzzle device, one with MonsterMan Grip, fixed stock and no muzzle device and one with a Hera Arms CQR stock and no muzzle device.
In September 2017 Ruger introduced the AR-556 MPR Multi-Purpose Rifle, fitted with a Magpul MOE grip, a Magpul MOE SL collapsible buttstock, a free-floating M-LOK handguard, a Ruger Elite 452 two-stage trigger, a nitrided cold hammer-forged barrel with 1:8" twist 5R rifling, and a Ruger muzzle brake.
Ruger's introduction of the SR-556 was met with some criticism for its high price tag (around U.S. $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 rifles, which lack a forward assist or 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.
- "Ruger SR-556". Sturm, Ruger, and Co., Inc. Retrieved 9 December 2012.
- Gilbert, Glenn M., Ruger's SR-556: Ready To Run, Right Out Of The Box, American Rifleman, October 2009
- 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.
- Cumpston, Mike. "Ruger's SR-556E 5.56mm NATO". Guns. 51 (12): 56.
|Wikimedia Commons has media related to Ruger SR-556.|