USED Duramag Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine 50 Pack Black/Blue 4. When you don't need capacity though and prioritize ergonomics and comfort the Duramag SS Flush-Fit magazines are a perfect solution for both your Gen 1 and Gen 2 Ruger American rifles with the OEM stock / mag-well for AR pattern magazines. Specifications for Duramag Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine: Manufacturer: Duramag Color: Black/Blue Magazine Capacity: 4 Round Caliber: .22 ARC (Advanced Rifle Cartridge) 6mm ARC 6.5mm Grendel Gun Make: Ruger Gun Model: Ruger American Rifle Gun Type: Rifle Package Contents: Duramag Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine What firearm models does the manufacturer say Duramag Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine is compatible with? The manufacturer suggests that Duramag Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine is compatible with Ruger American RifleDuramag 4X650F41176CPD: Ruger American Rifle 6.5 Grendel/6mmARC /22ARC 4 Round Rifle Magazine 50 Pack Black/Blue