Promag DPM-A1 - DPMS / SR-25 .308 Win. 20 Rpund Black Phosphate Steel Magazine. .308 Winchester, 20-rd magazine for DPMS LR-308, and SR-25 Rifles. Magazine body Constructed of heat treated steel with a black phosphate finish for durability under harsh use in the field. A Chrome-silicon wire spring and precision molded polymer follower ensure reliable feeding and function.