Physics

Ballistic Coefficient Calculator

Find a projectile's ballistic coefficient.

Bullet weight (gr)

Diameter

Form factor i

Calculated Output

Ballistic coefficient 0.4518

Sectional density 0.2259

Formula: BC = SD ÷ i; SD = (weight/7000) ÷ diameter²

Step-by-Step Breakdown

1. Values used:

2. Bullet weight = 150 gr

3. Diameter = 0.308

4. Form factor i = 0.5

6. Ballistic coefficient = 0.4518

7. Sectional density = 0.2259

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The math behind it

BC = sectional density ÷ form factor. Sectional density = (weight in lb) ÷ diameter². Higher BC means less drop and drift.

150 gr, .308", form factor 0.5 → SD 0.226, BC 0.452.

What is the form factor?

How a bullet's shape compares to a standard reference projectile.