When the barrel of a firearm is aligned parallel to the ground, establishing a trajectory initially perpendicular to gravity’s influence, this is referred to as zero elevation. A projectile fired under these conditions experiences a downward acceleration due to gravity from the moment it leaves the muzzle, while simultaneously maintaining its horizontal velocity (ignoring air resistance). This results in a curved flight path. A practical example of this principle is seen in long-range shooting where understanding this initial horizontal trajectory is crucial for accurate placement of shots.
This concept is fundamental to marksmanship and external ballistics. Historically, understanding projectile motion under gravity was a key development in warfare and hunting. Mastering this principle allows for precise calculations of range and necessary adjustments for various environmental factors such as wind and even the Earth’s rotation (Coriolis effect) at longer distances. It forms the basis for sighting systems and ballistic tables used by military and civilian shooters alike.