Instructions
Choose a weapon with high power, such as a sniper rifle or shotgun. These weapons can maintain speed and produce higher damage even when traveling through a box.
Get as close to the box as you can. The closer you are to the object, the higher the chance the bullet will be able to pass through it. Additionally, the closer you are when shooting through an object, the more damage it will do.
Point at the box and fire several shots. If you know the exact location of the person, you can fire into one concentrated area. If you are unsure of where exactly the opponent is located behind the box, you can scatter your shots across the box to eventually force him out of cover.