Yes, the Giant Dragons successfully conducted the bombardment, but the effect was minimal. The Giant Dragons didn't even know how thick the enemy's armor really was!
The bombing continued, and the most effective Armor-Piercing Bombs could only blast open about ten meters of armor each time. However, it was impossible for the Armor-Piercing Bombs to hit the same position precisely every time. Twenty minutes passed in a blink of an eye, and the immense Dragon Ball still floated there. As the cracks closed, the Worm's sneering voice came through: "Struggle, Simu, for you no longer have much time left. I am very much looking forward to seeing the despair in your eyes when the crack opens next time!"
The crack closed.