撃墜 （ゲキツイ） shooting down (aircraft)

撃沈 （ゲキチン） sending a ship to the bottom, sinking (a ship), to sink a ship

銃撃 （ジュウゲキ） shooting, gunning (down)

追撃 （ツイゲキ） pursuit (of a fleeing enemy), chase

撃つ （うつ） to shoot, to fire

討つ （うつ） to attack, to destroy, to defeat, to conquer, to avenge