The Ruger 10-round chassis magazine fits the Ruger Precision Rifle and Gunsite SCout Rifle chambered in 5.56 NATO/223 Rem. 60% glass-filled polymer design for strength and durability. Stainless steel spring provides reliable feeding and corrosion resistance. Designed to function with many Al-style bottom metal assemblies in .223 Rem-sized cartridges with a COAl max of 2.50". Dust cover protects rounds from damage and debris during transportation and storage.