The SR-556U6.8 is typical Ruger, well engineered and very robust. This, along with the gas piston system, should assure an extremely reliable and rugged firearm. Ruger is no fan of the AR15 type direct impingement gas system, so they chose the gas piston system. Ruger chose not to just build another AR15 clone. They chose to build from the best options out there.
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