Ruger OEM American Rifle Multi-Caliber Magazine Black 308 Winchester Rifle Magazine - 4 Rounds - This 4-round, .308 Multi-Caliber Genuine Ruger Factory Magazine is compatible with the Ruger American Rifle. This polymer flush-fit magazine works with short-action rounds including the .308 Win., 6.5 Creedmoor, 6mm Creedmoor, .243 Win., and 7mm-08 Rem. Genuine Ruger Factory Accessory.