Recoil Energy Calculator

What Is Recoil Energy?

When a firearm fires, the bullet moves forward and the gun kicks backward. Momentum is conserved: the bullet's forward momentum equals the gun's backward momentum. The gun's recoil kinetic energy depends on its mass and recoil velocity.

Recoil Physics Formulas

From conservation of momentum:

$$m_b v_b = m_g v_g$$

Recoil velocity and kinetic energy are:

$$v_g = \frac{m_b v_b}{m_g}$$ $$KE_{\text{recoil}} = \frac{1}{2} m_g v_g^2$$

A heavier gun absorbs the same momentum with less velocity and much less kinetic energy. That is why large-caliber rifles feel sharper when the gun is light.

Factors Affecting Felt Recoil

Bullet mass, muzzle velocity, gun weight, stock design, and muzzle devices all influence perceived recoil. This calculator gives the free-recoil energy of the firearm itself before accounting for the shooter's body mass.

Frequently Asked Questions

How is recoil velocity calculated?

Recoil velocity equals bullet mass times bullet velocity divided by gun mass, from momentum conservation. Both masses must be in kilograms and velocity in meters per second.

Why is gun mass important for recoil?

A heavier gun moves slower for the same bullet momentum, and kinetic energy scales with velocity squared. Doubling gun mass cuts recoil velocity in half and recoil energy to one quarter.

What units should I use for bullet mass?

Enter bullet mass in grams. The calculator converts to kilograms internally. Gun mass is entered in kilograms.

Does this include the shooter's body?

No. This tool calculates free recoil of the firearm only. The shooter's mass further reduces felt motion when the gun is held firmly against the shoulder.

What is a typical recoil energy for a rifle?

Light rifles may produce 5 to 15 joules of free recoil energy. Heavy magnum cartridges on light platforms can exceed 30 joules. Handguns are usually lower due to smaller bullet momentum.

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What Is Recoil Energy?

Recoil Physics Formulas

Factors Affecting Felt Recoil

Frequently Asked Questions

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