The SR-556 is an AR-15 style semi-automatic rifle manufactured ...
wikipedia - 24 Mar 2021The SR-556 is an AR-15 style semi-automatic rifle manufactured by U.S. firearms company 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.[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.
