arma arma operation arrowhead as i understand it bohemia hasn t released any sales numbers for arma and it s standalone expansion operation arrowhead but considering that on the official site of the dayz mod there are over million unique legal users both arma and arma oa have sold at least m copies each obviously they sold more but that s the only metric available so i suppose both of them can be added to the list either by listing each at m or just like guild wars putting both together at millions thanks