Air guns are classified as low-velocity missiles and they usually considered safe and harmless. Despite that fact, air guns still can make serious or life-threatening injuries. Most of air gun injuries occur in paediatric population. A 2-year-old boy was shot in the forehead withan air gun accidentally. Skull radiography and non-contrast CT scan of the head were performed and showed penetrating bihemispheric brain injury from the left frontal to right occipital lobes at the level of the lateral ventricle with a metal-density foreign body at the right occipital. A projectile was successfully extracted via craniotomy, without complications. Air guns have the potential to cause fatal, life-threatening injury especially in children. Imaging is crucial for the evaluation of wound ballistics. Understanding about the mechanism of projectiles and wound ballistics is very helpful for radiologists to conceptualize these injuries when interpreting these cases. The role of radiology in ballistic wound cases is critical and important, both for clinical and forensic settings.