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Bullet Spin Rate (BSP) Calculator

Formula

The formula to calculate the Bullet Spin Rate (BSP) is:

$BSP = \frac{MV \times 720}{BTR}$

Where:

BSP is the Bullet Spin Rate (RPM)
MV is the muzzle velocity (fps)
BTR is the barrel twist rate

What is Bullet Spin Rate?

The Bullet Spin Rate (BSP) is a measure of how fast a bullet spins as it travels through the air. It is calculated by dividing 720 by the barrel twist rate and then multiplying by the muzzle velocity. This rate is crucial for understanding the stability and accuracy of the bullet in flight.

Example Calculation

Example 1:

Muzzle Velocity: 3000 fps
Barrel Twist Rate: 10

Calculation:

$BSP = \frac{3000 \times 720}{10} = 216000 \text{ RPM}$

Example 2:

Muzzle Velocity: 2500 fps
Barrel Twist Rate: 12

Calculation:

$BSP = \frac{2500 \times 720}{12} = 150000 \text{ RPM}$