Barrett Single Feed Adapter, Fits MRAD ELR, Black, 1 Round 19592 More than forty years ago" Ronnie Barrett built something no one thought possible - a shoulder-red .50 caliber rie so innovative" the Army itself would sing its praises. From sketching his designs at the dining room table to working with a local tool and die maker to create parts that didn't yet exist" every millimeter of the Model 82 was a direct result of Ronnie's passion for the ultimate rearm.