What is ballistic coefficient (BC)?

BC measures how well a bullet resists air drag relative to a reference projectile. Higher BC = less drag = less wind drift. G1 BC is based on a flat-based reference bullet and is common for pistol and hunting bullets. G7 BC uses a boat-tail reference and is more accurate for long-range rifle bullets. Use whichever your ammo manufacturer publishes.

Why does wind angle matter?

Only the crosswind component (perpendicular to your line of fire) causes lateral drift. A pure headwind or tailwind produces zero lateral drift. The crosswind component = wind speed × sin(angle). A 90° angle is a full-value crosswind; 45° is a half-value; 0° and 180° are zero.

How accurate is this calculator?

The lag-time method gives a good first approximation at moderate ranges. At very long ranges (beyond 600 yards / 550 m) the simplified drag model diverges from measured data. For competition precision work, use a full ballistic solver that integrates the drag curve. This tool is best for field estimates and education.

What is a typical BC for a rifle bullet?

Hunting and varmint bullets typically range G1 BC 0.25–0.45. Match-grade long-range bullets run G1 BC 0.50–0.65 or G7 BC 0.25–0.33. Pistol bullets are usually G1 BC 0.10–0.20. Check your bullet's spec sheet for the published value.

What is muzzle velocity and where do I find it?

Muzzle velocity (MV) is the bullet's speed as it leaves the barrel, measured in fps (feet per second) or m/s. It is printed on the ammo box or in the cartridge spec sheet. Typical rifle loads: 2,600–3,300 fps. Pistol: 800–1,400 fps.

Bullet Wind Drift Calculator

Name: Bullet Wind Drift Calculator
Availability: InStock
Author: Nham Vu

Enter wind speed, wind angle, distance, and ballistic coefficient to estimate how far a bullet drifts off-course at the target.

Wind Drift Parameters

Muzzle Velocity (fps)

Rifle: 2,600–3,300 fps. Pistol: 800–1,400 fps.

Drag Model

Ballistic Coefficient (BC) (G1 or G7)

G1 hunting/match: 0.25–0.65. G7 match: 0.25–0.35.

Wind Speed (mph)

Wind Angle (degrees from line of fire)

0°/180° = head/tailwind (no drift). 90° = full crosswind.

Blue dashed = wind direction relative to shot.

Target Distance (yards)

Drift at Distance

Distance	Drift	MOA

Wind Value Reference

0° or 180° (head/tail) 0.0× value

30° or 150° 0.5× value

45° or 135° 0.7× value

90° (full cross) 1.0× value

Summary