8magnesium alloy qq-m-38, alloy 30 grade bbc 42-008-71; 4.000 in. O.D.; 2.890 in. I.D.; 0.773 in. O/a dp; 0.094 in. Wall thickness; 3 holes irregularly spaced, 0.140 in. Drill thru; 4 holes equally spaced, 0.089 in. Drill thru, threaded, on 3.718 in. Dia