ProMag Rifle Magazine AR-308 .308 Win 20 Round Blued 1 Pack Steel 20RD. It is constructed of heat treated steel with blued finish injection molded mag follower & mag spring formed from heat treated chrome silicon wire. Note: Does not fit rifles using the Armalite pattern magazines. Specifications for ProMag AR-308 .308 Win 20-Round Rifle Magazine: Manufacturer: ProMag Color: Blued Fabric/Material: Steel Magazine Capacity: 20 Round Caliber: .308 Winchester Gun Make: AR Platform Gun Model: AR-10 Condition: New Features of ProMag Steel AR-308 .308 20-Round Rifle Magazine Magazine body constructed of heat treated steel with black oxide finish Injection molded magazine follower Magazine spring formed from heat treated chrome silicone wire Package Contents: ProMag AR-308 .308 Win 20-Round Rifle Magazine What firearm models does the manufacturer say ProMag AR-308 .308 Win 20-Round Rifle Magazine is compatible with? The manufacturer says that ProMag AR-308 .308 Win 20-Round Rifle Magazine is compatible with AR-10ProMag DPMA1-20RD: Rifle Magazine AR-308 .308 Win 20 Round Blued 1 Pack Steel