 Complete the following phrase:  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 Musashis guns during the Battle of the Sibuyan Sea. Four bombers from the USS Intrepid were reportedly shot down by the Musashis Sanshiki shells during the Sibuyan Sea engagement. Yamato fired these shells in two separate instances during 