Bullet Drop and External Ballistics Calculator
Calculate bullet drop, velocity at range, and scope correction in MOA or mils.
Based on muzzle velocity and ballistic coefficient for any caliber.
External Ballistics External ballistics covers the flight of a projectile after it leaves the barrel. Gravity constantly accelerates the bullet downward at 9.81 m/s². The bullet drops below the line of bore, not the line of sight. A scope sits above the bore — the bullet crosses the line of sight twice (near zero and far zero).
Simplified Drop Formula (no air resistance) Drop (vacuum) = ½ × g × t² Where t = time of flight = range / muzzle_velocity (approximation without drag). In reality, air drag slows the bullet and increases time of flight, increasing drop.
G1 Ballistic Coefficient The BC (G1) measures how efficiently a bullet retains velocity against drag. Higher BC = less drag = less drop. Typical G1 BCs: .22 LR: 0.13–0.16 | .308 168gr: 0.475 | 6.5 Creedmoor 147gr: 0.697 .338 Lapua 250gr: 0.587 | .50 BMG 750gr: 0.950
Approximate Trajectory with Drag (Pejsa model) This calculator uses a simplified atmospheric drag model for practical field use. For precision long-range work, use Hornady 4DOF or Applied Ballistics software.
Scope Adjustment MOA (Minute of Angle): 1 MOA ≈ 1.047 inches at 100 yards (close enough to 1 inch). MRAD (Mil-radian): 1 mil = 10 cm at 100 m = 3.6 inches at 100 yards. Convert drop to MOA: MOA = drop_inches / (range_yards / 100) Convert drop to mils: mils = drop_cm / (range_m / 10)
Zero Range A typical 100-yard zero means the bullet is at the same height as the crosshair at 100 yards. The bullet is typically 1.5" high at 50 yards (for a 100-yd zero). Long-range shooters often use a 200-yard zero to minimize mid-range correction.