A bullet’s journey of one mile (1,760 yards) is a complex study in physics. The time it takes for a projectile to cover this extreme distance is not a fixed number but a variable dependent on the cartridge, the bullet’s design, and atmospheric conditions. Understanding this flight time requires looking at the science of ballistics, which governs the forces acting on the bullet from the moment it leaves the barrel until it reaches the target.
The Quantitative Answer
The travel time for a bullet to cover one mile varies significantly, falling within a broad range of approximately 2 to over 12 seconds. A high-performance, long-range cartridge, such as the .338 Lapua Magnum, is designed specifically for such distances and can achieve a flight time of around 3 to 4 seconds. This speed is possible because of the bullet’s aerodynamic design and high initial velocity.
A common, lower-powered round like the .22 Long Rifle (.22 LR) takes a much longer path. For the .22 LR to even reach one mile, it must be fired at a steep upward angle, and its flight time can extend to 12 seconds or more. Even a popular medium-power round like the .308 Winchester, which is not optimized for this extreme range, may take nearly 4 seconds to travel one mile.
Understanding Exterior Ballistics
The reason for the variability in travel time is exterior ballistics, which describes the projectile’s behavior after it leaves the firearm’s muzzle. The three primary factors determining a bullet’s flight are its muzzle velocity, ballistic coefficient, and the force of air drag. These elements combine to determine how efficiently the bullet travels through the atmosphere.
Muzzle velocity is the initial speed of the bullet as it exits the barrel. This speed immediately begins to decrease because of air resistance, a decelerating force called drag. The ballistic coefficient is a numerical measure of a bullet’s ability to overcome this air drag, reflecting how aerodynamic the projectile is. A higher ballistic coefficient means the bullet maintains its speed more effectively, resulting in a shorter flight time.
Velocity Loss and Bullet Drop Over One Mile
Traveling one mile is an extreme distance that maximizes the effects of atmospheric resistance and gravity. The bullet loses a substantial amount of its initial velocity over this range, with high-performance rounds often losing over half their speed by the time they reach the mile mark. This deceleration dramatically increases the time the bullet spends in the air, which amplifies the effect of gravity.
The consequence of this extended flight time is a massive amount of bullet drop, the vertical distance the projectile falls. For a successful one-mile shot, the shooter must aim significantly higher than the target to compensate for this drop, which can measure hundreds of feet. For instance, a high-powered .338 Lapua Magnum bullet may drop over 200 feet, requiring extreme upward adjustment. This substantial drop means the bullet is traveling in a high, arcing trajectory, much like a miniature artillery shell.
Comparing Bullet Speed to Sound
The speed of a bullet is often compared to the speed of sound, referred to as Mach 1 (approximately 1,125 feet per second). Many high-powered bullets start their journey at supersonic speeds, traveling faster than Mach 1, often in the range of 2,800 to over 3,000 feet per second.
The rapid velocity loss over the mile distance means that many bullets transition from a supersonic to a subsonic state before reaching the target. This transition point, where the bullet slows to less than Mach 1, can introduce instability that makes accuracy difficult. Even the efficient .338 Lapua Magnum, which attempts to remain supersonic for as long as possible, may slow to below 1,000 feet per second by the one-mile mark. This terminal speed is often comparable to or slower than the initial speed of a common handgun round.