THE AR PLATFORM REDEFINED The SR-556 offers Ruger’s legendary rugged reliability, and comes factory standard with a host of accessories that today’s shooters demand. Employing a patent-pending, chrome-plated, two-stage piston driven operating system that provides the user with a cleaner, cooler running, reliable firearm that is truly state-of-the-art. The chrome-lined gas block and chrome-plated piston and regulator work together to provide a smooth power delivery stroke to the bolt carrier. The by-products of the gas system are vented out the bottom of the gas block, away from the bolt carrier, keeping the action clean and free from contaminants. The end result is significantly improved performance over gas driven rifles. Features Two stage piston with adjustable regulator Chrome plated bolt 16.12″ Cold hammer-forged, chrome lined mil spec barrel Quad rail handguard Folding back-up iron sights Six position Telescoping M4-style buttstock Hogue Monogrip pistol grip for comfort Supplied with 2 x 30 round Magpul PMAG magazines Soft sided case included Note: Restricted sale to Cat: D licence holders only