The SR-556 offers Ruger's legendary rugged reliability, redefining the AR platform with piston driven performance. The piston driven SR-556 runs cleaner, cooler, and is easier to maintain than gas driven rifles, offering significantly improved reliability.
http://www.ammoland.com/2009/05/18/ruger-ar-sr-556-autoloading-rifle/
:30
:30
:30
:47
:48
3:24
2:43
:31