Instruction Manual for Ruger Mini-14 Rifle. and 50 similar items Instruction Manual for Ruger Mini-14 Rifle. .223. 5.56mm Caliber.Paperback -1979Instruction Manual Ruger Mini 14 - Select a firearm below to view its Instruction Manual, Serial Number and Caliber History.. Cold hammer-forged barrel results in ultra-precise rifling that provides exceptional accuracy, longevity and easy cleaning. Simple, rugged, Garand-style action with breechbolt locking system, a fixed-piston gas system and self-cleaning moving gas cylinder gives unparalleled reliability.