B-17s were used in early battles of the Pacific with little success, notably the Battle of Coral Sea[112] and Battle of Midway.[113] While there, the Fifth Air Force B-17s were tasked with disrupting the Japanese sea lanes. Air Corps doctrine dictated bombing runs from high altitude, but it was soon discovered that only one percent of their bombs hit targets. However, B-17s were operating at heights too great for most A6M Zero fighters to reach, and the B-17's heavy gun armament was more than a match for lightly protected Japanese aircraft.