Even though the "3 Shiki tsûjôdan" shells comprised 40% of the total main ammunition load of the "Yamato"-class battleships by 1944, they were rarely used in combat against enemy aircraft. The blast of the main guns turned out to disrupt the fire of the smaller antiaircraft guns. In addition the copper drive bands of the rounds were poorly machined and constant firing was damaging the gun rifling; indeed, one of the shells may have exploded early and disabled one of "Musashi"s guns during the Battle of the Sibuyan Sea. Four bombers from the USS "Intrepid" were reportedly shot down by the "Musashi's" Sanshiki shells during the Sibuyan Sea engagement. "Yamato" fired these shells in two separate instances during Operation Ten-Go, first against PBM Mariner flying boats shadowing her, and later against the attacking aircraft of Task Force 58.