. "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 platform rifles to use gas piston operation."@en . . "Ruger SR-556"@en . "0.0635"^^ . . "3601.58"^^ . "0.83185"^^ . "0.19685"^^ .