Ruger SR-556
The SR-556 was a semi-automatic AR-15 style rifle manufactured by Sturm, Ruger & Co. The rifle was introduced in 2009 in .223 Remington/5.56×45mm NATO and as a .308 Winchester AR-10 variant in 2013, the SR-762. It is one of several AR-15 rifles to use a gas piston operation.
History
Ruger announced on May 15, 2009 on the SR-556 being produced. On May 13, 2010, the SR-556C was announced.In January 2016, Ruger discontinued all SR-556 rifles and introduced a new takedown variant, known as the Ruger SR-556 Takedown, with a lightweight KeyMod handguard in 2017.
Design
The rifle features a short-stroke piston mechanism as opposed to the semi-direct impingement system of the AR-15. Gas flow is controlled by a four position regulator. Several key parts, such as the 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 suppressor is similar to Ruger's AC-556 and Mini-14GB.The 5.56 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 STANAG magazines. The 7.62 variant uses SR-25 pattern 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, chrome lined, and features a six groove, right hand, 1: twist.
In August 2010, Ruger announced that the rifle would be offered in the 6.8mm Remington SPC cartridge.
Criticism
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, but with a piston operated gas system instead of the standard direct impingement system. It differs from the less expensive alternatives like the Smith & Wesson M&P15 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 being heavier than other AR-15s.Ruger addressed these shortcomings by introducing a lighter and less expensive rifle, the SR-556E.