The Ready Series® ZRO1 is the foundational offering of the Ready Series®. The ZRO1 combines all of the durability and reliability the Ready Series® is known for with streamlined features. Featuring an ambidextrous bolt release, 16” nitride barrel chambered in .223 Wylde chamber, and a 15” MLOK rail, the ZRO1 is ready for your optic of choice and a lifetime of reliable service. Hard working Americans manufacture, assemble, and test each ZRO1 with pride. The 223 Wylde chamber allows using either 5.56 NATO ammunition or 223 Rem ammunition.